Combobox (input / dropdown box combined)
I Found this very handy combobox script and thought it may help others
Credits goto Author: COMBOBOX in HTML: Editable Dropdown Listbox. Select Option is Editable. Javascript. 
PHP Code:
<!--
***************************************************************
http://chakrabarty.com/pp_editable_dropdown.html
http://chakrabarty.com/combobox.html
***************************************************************
Hi,
I have written a set of javascript functions for an "Editable Dropdown (/Listbox/Combobox)"...
FEATURES:
1.Any one of the dropdown options can be made Editable (for example either the first or last option can be made editable).
2.Rest of the options are read-only (as in a normal dropdown).
3.Press [ <- ] and [ -> ] arrow keys on the keyboard to change alignment/flow.
...go to Start : Press [ <- ] Arrow Key
...go to End : Press [ -> ] Arrow Key
(In Internet Explorer: this is useful when the edited-text content exceeds the fixed-width of the dropdown. This is Not useful in NetscapeFirefoxChrome)
4.Editable Option: Press "BackSpace" to remove the last typed character .
5.Editable Option: Press "Delete" to remove all typed characters .
6.The Editable Dropdown can be customized to the following formats:
--------------------------------------------
(a) Left Aligned,
VARIABLE WIDTH,
Left To Right Flow
--------------------------------------------
(b) Left Aligned,
FIXED WIDTH,
Left To Right Flow
--------------------------------------------
(c) RIGHT Aligned,
Variable Width,
RIGHT TO LEFT FLOW
(Content flows right to left)
--------------------------------------------
(d) RIGHT Aligned,
FIXED Width,
RIGHT TO LEFT FLOW
(Content flows right to left)
--------------------------------------------
7.Does not tolerate the "Backspace" bug or "automatic Jump" bug (explained in next section).
8.The characters to be allowed/disallowed in Editable Option can be customized.
This can be done by using statements such as:
if(vEventKeyCode == ascii#_of_character) then ...
You just need to know the keycode/ASCII value of the character you want
to allow/disallow.
9.Overcomes all the bugs I have come across in other logic/codes for Editable dropdowns.
It works beautifully !!!
----------------------------------------------------------------------
NO BUGS:
This code does NOT have the following bugs that are commonly associated with Editable Dropdown codes :
1. "Backspace" bug :
A "Backspace" keypress in the dropdown works like a BACK button on the Browser !!
(...hence editing is hampered )
2. The "automatic Jump" bug:
If a alphabet is entered (while editing)
... which is a first character in one of the other read-only options
... then the focus automatically "jumps" to that read-only option
(* this is a common property of normal dropdowns
..but..is undesirable while editing).
3. CAPS bug :
Values Entered are always displayed in CAPS ....lower case not possible.
4. Javascript error: For example, when dropdown is empty and a key is pressed.
5. Limited Characters Bug: Some codes do not allow certain characters.
But in this code, you decide the characters to be allowed (see point 8 above).
The new set of functions I have written do not have the above bugs.
Hope you will find this code useful.
Best regards,
Author (source: http://chakrabarty.com/pp_editable_dropdown.html )
-->
<!--
***************************************************************
TWO STEPS TO INSTALL EDITABLE DROP DOWN - source: http://chakrabarty.com/pp_editable_dropdown.html.:
1. Copy the first part of the coding (javascript) into the HEAD of your HTML document
2. Add the last part of code (HTML) into the BODY of your HTML document
STEPS TO MANIPULATE/OPERATE EDITABLE DROP DOWN - source: http://chakrabarty.com/pp_editable_dropdown.html.:
1. IMPORTANT: Deciding which option is "Editable"...
Two Global Variables required to be SET by programmer:
var vEditableOptionIndex...;
Give Index of Editable option in the dropdown.
For eg.
if first option is editable then vEditableOptionIndex = 0;
if second option is editable then vEditableOptionIndex = 1;
if third option is editable then vEditableOptionIndex = 2;
if last option is editable then vEditableOptionIndex = (length of dropdown - 1).
Note: the value of vEditableOptionIndex cannot be greater than (length of dropdown - 1)
var vEditableOptionText...;
Give the default text of the Editable option in the dropdown.
For eg.
if the editable option is <option ...>--?--</option>,
then set vEditableOptionText = "--?--";
2. Setting the Width, Alignment and Flow features of the dropdown:
--------------------------------------------
(a) The code available below will give the
Editable Dropdown in the format:
Left Aligned,
VARIABLE WIDTH,
Left To Right Flow
--------------------------------------------
(b) To Change the Editable Dropdown to the format:
Left Aligned,
FIXED WIDTH,
Left To Right Flow
in the SELECT option (in the BODY of your HTML document),
give style="width:150px;".
<SELECT style="width:150px;"
* Not giving the width style will make it 'variable'.
* You may vary the fixed width by altering width in the style="width:150px;"
--------------------------------------------
(c) To Change the Editable Dropdown to the format:
RIGHT Aligned,
Variable Width,
RIGHT TO LEFT FLOW
(Content flows right to left)
add / include
style="direction:rtl;"
into the SELECT option
(in the BODY of your HTML document), i.e.,
<SELECT style="direction:rtl;"
... leaving the rest of the parameters as they are.
--------------------------------------------
(d) To Change the Editable Dropdown to the format:
RIGHT Aligned,
FIXED Width,
RIGHT TO LEFT FLOW
(Content flows right to left)
add / include
style="width:150px;direction:rtl;"
into the SELECT option
(in the BODY of your HTML document), i.e.,
<SELECT style="width:150px;direction:rtl;"
... leaving the rest of the parameters as they are.
( you may vary the fixed width by altering the style="width:150px;" )
--------------------------------------------
***************************************************************
** Note : you may wish to simply select-all and copy the entire
contents of this script and save it as a html for testing etc..
***************************************************************
***************************************************************
-->
<!--
************************************************************
************************************************************
STEP ONE: Paste the following code into
the HEAD of your HTML document
************************************************************
************************************************************
-->
<!--******* Start of "HTML" document *******-->
<html>
<!--******* Start of "HEAD" (of HTML document) *******-->
<head>
<meta name="keywords" content="combobox, javascript, html, editable, edit, dropdown, listbox, list, combo, box, menu">
<meta name="author" content="Subrata Chakrabarty">
<meta name="description" content="COMBOBOX in HTML: Editable Dropdown. Javascript. One select option is Editable (like a textbox) and the rest are readonly (like a normal dropdown/listbox)">
<meta name="robots" content="noindex,follow,noodp,noarchive,nosnippet">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="pragma" content="no-cache">
<title>Combobox -- Editable Dropdown / Listbox -- HTML JavaScript</title>
<script language="JavaScript"> //Common functions for all dropdowns
/*--------------------------------------------------------------
http://chakrabarty.com/pp_editable_dropdown.html
http://chakrabarty.com/combobox.html
--------------------------------------------------------------*/
/*----------------------------------------------
The Common functions used for all dropdowns are:
-----------------------------------------------
-- function FindKeyCode(e)
-- function FindKeyChar(e)
-- function fnLeftToRight(getdropdown)
-- function fnRightToLeft(getdropdown)
--------------------------- source: http://chakrabarty.com/pp_editable_dropdown.html */
function fnLeftToRight(getdropdown)
{
getdropdown.style.direction = "ltr";
}
function fnRightToLeft(getdropdown)
{
getdropdown.style.direction = "rtl";
}
/*
Since Internet Explorer and NetscapeFirefoxChrome have different
ways of returning the key code, displaying keys
browser-independently is a bit harder.
However, you can create a script that displays keys
for either browser.
The following function will display each key
in the status line:
The "FindKey.." function receives the "event" object
from the event handler and stores it in the variable "e".
It checks whether the "e.which" property exists (for NetscapeFirefoxChrome),
and stores it in the "keycode" variable if present.
Otherwise, it assumes the browser is Internet Explorer
and assigns to keycode the "e.keyCode" property.
*/
function FindKeyCode(e)
{
if(e.which)
{
keycode=e.which; //NetscapeFirefoxChrome
}
else
{
keycode=e.keyCode; //Internet Explorer
}
//alert("FindKeyCode"+ keycode);
return keycode;
}
function FindKeyChar(e)
{
keycode = FindKeyCode(e);
if((keycode==8)||(keycode==127))
{
character="backspace"
}
else if((keycode==46))
{
character="delete"
}
else
{
character=String.fromCharCode(keycode);
}
//alert("FindKey"+ character);
return character;
}
</script>
<script language="JavaScript"> //Dropdown specific functions, which manipulate dropdown specific global variables
/*----------------------------------------------
Dropdown specific global variables are:
-----------------------------------------------
1) vEditableOptionIndex_A --> this needs to be set by Programmer!! See explanation.
2) vEditableOptionText_A --> this needs to be set by Programmer!! See explanation.
3) vPreviousSelectIndex_A
4) vSelectIndex_A
5) vSelectChange_A
--------------------------- source: http://chakrabarty.com/pp_editable_dropdown.html */
/*----------------------------------------------
Dropdown specific functions
(which manipulate dropdown specific global variables)
-----------------------------------------------
1) function fnChangeHandler_A(getdropdown)
2) function fnKeyPressHandler_A(getdropdown, e)
3) function fnKeyUpHandler_A(getdropdown, e)
4) function fnKeyDownHandler_A(getdropdown, e)
--------------------------- source: http://chakrabarty.com/pp_editable_dropdown.html */
/*------------------------------------------------
IMPORTANT: Global Variable required to be SET by programmer
-------------------------- source: http://chakrabarty.com/pp_editable_dropdown.html */
var vEditableOptionIndex_A = 0;
// Give Index of Editable option in the dropdown.
// For eg.
// if first option is editable then vEditableOptionIndex_A = 0;
// if second option is editable then vEditableOptionIndex_A = 1;
// if third option is editable then vEditableOptionIndex_A = 2;
// if last option is editable then vEditableOptionIndex_A = (length of dropdown - 1).
// Note: the value of vEditableOptionIndex_A cannot be greater than (length of dropdown - 1)
var vEditableOptionText_A = "--?--";
// Give the default text of the Editable option in the dropdown.
// For eg.
// if the editable option is <option ...>--?--</option>,
// then set vEditableOptionText_A = "--?--";
/*------------------------------------------------
Global Variables required for
fnChangeHandler_A(), fnKeyPressHandler_A() and fnKeyUpHandler_A()
for Editable Dropdowns
-------------------------- source: http://chakrabarty.com/pp_editable_dropdown.html */
var vPreviousSelectIndex_A = 0;
// Contains the Previously Selected Index, set to 0 by default
var vSelectIndex_A = 0;
// Contains the Currently Selected Index, set to 0 by default
var vSelectChange_A = 'MANUAL_CLICK';
// Indicates whether Change in dropdown selected option
// was due to a Manual Click
// or due to System properties of dropdown.
// vSelectChange_A = 'MANUAL_CLICK' indicates that
// the jump to a non-editable option in the dropdown was due
// to a Manual click (i.e.,changed on purpose by user).
// vSelectChange_A = 'AUTO_SYSTEM' indicates that
// the jump to a non-editable option was due to System properties of dropdown
// (i.e.,user did not change the option in the dropdown;
// instead an automatic jump happened due to inbuilt
// dropdown properties of browser on typing of a character )
/*------------------------------------------------
Functions required for Editable Dropdowns
-------------------------- source: http://chakrabarty.com/pp_editable_dropdown.html */
function fnSanityCheck_A(getdropdown)
{
if(vEditableOptionIndex_A>(getdropdown.options.length-1))
{
alert("PROGRAMMING ERROR: The value of variable vEditableOptionIndex_... cannot be greater than (length of dropdown - 1)");
return false;
}
}
function fnKeyDownHandler_A(getdropdown, e)
{
fnSanityCheck_A(getdropdown);
// Press [ <- ] and [ -> ] arrow keys on the keyboard to change alignment/flow.
// ...go to Start : Press [ <- ] Arrow Key
// ...go to End : Press [ -> ] Arrow Key
// (this is useful when the edited-text content exceeds the ListBox-fixed-width)
// This works best on Internet Explorer, and not on NetscapeFirefoxChrome
var vEventKeyCode = FindKeyCode(e);
// Press left/right arrow keys
if(vEventKeyCode == 37)
{
fnLeftToRight(getdropdown);
}
if(vEventKeyCode == 39)
{
fnRightToLeft(getdropdown);
}
// Delete key pressed
if(vEventKeyCode == 46)
{
if(getdropdown.options.length != 0)
// if dropdown is not empty
{
if (getdropdown.options.selectedIndex == vEditableOptionIndex_A)
// if option is the Editable field
{
getdropdown.options[getdropdown.options.selectedIndex].text = '';
getdropdown.options[getdropdown.options.selectedIndex].value = '';
}
}
}
// backspace key pressed
if(vEventKeyCode == 8 || vEventKeyCode == 127)
{
if(getdropdown.options.length != 0)
// if dropdown is not empty
{
if (getdropdown.options.selectedIndex == vEditableOptionIndex_A)
// if option is the Editable field
{
// make Editable option Null if it is being edited for the first time
if ((getdropdown[vEditableOptionIndex_A].text == vEditableOptionText_A)||(getdropdown[vEditableOptionIndex_A].value == vEditableOptionText_A))
{
getdropdown.options[getdropdown.options.selectedIndex].text = '';
getdropdown.options[getdropdown.options.selectedIndex].value = '';
}
else
{
getdropdown.options[getdropdown.options.selectedIndex].text = getdropdown.options[getdropdown.options.selectedIndex].text.slice(0,-1);
getdropdown.options[getdropdown.options.selectedIndex].value = getdropdown.options[getdropdown.options.selectedIndex].value.slice(0,-1);
}
}
}
if(e.which) //NetscapeFirefoxChrome
{
e.which = '';
}
else //Internet Explorer
{
e.keyCode = '';
}
if (e.cancelBubble) //Internet Explorer
{
e.cancelBubble = true;
e.returnValue = false;
}
if (e.stopPropagation) //NetscapeFirefoxChrome
{
e.stopPropagation();
}
if (e.preventDefault) //NetscapeFirefoxChrome
{
e.preventDefault();
}
}
}
function fnChangeHandler_A(getdropdown)
{
fnSanityCheck_A(getdropdown);
vPreviousSelectIndex_A = vSelectIndex_A;
// Contains the Previously Selected Index
vSelectIndex_A = getdropdown.options.selectedIndex;
// Contains the Currently Selected Index
if ((vPreviousSelectIndex_A == (vEditableOptionIndex_A)) && (vSelectIndex_A != (vEditableOptionIndex_A))&&(vSelectChange_A != 'MANUAL_CLICK'))
// To Set value of Index variables - source: http://chakrabarty.com/pp_editable_dropdown.html
{
getdropdown[(vEditableOptionIndex_A)].selected=true;
vPreviousSelectIndex_A = vSelectIndex_A;
vSelectIndex_A = getdropdown.options.selectedIndex;
vSelectChange_A = 'MANUAL_CLICK';
// Indicates that the Change in dropdown selected
// option was due to a Manual Click
}
}
function fnKeyPressHandler_A(getdropdown, e)
{
fnSanityCheck_A(getdropdown);
keycode = FindKeyCode(e);
keychar = FindKeyChar(e);
// Check for allowable Characters
// The various characters allowable for entry into Editable option..
// may be customized by minor modifications in the code (if condition below)
// (you need to know the keycode/ASCII value of the character to be allowed/disallowed.
// - source: http://chakrabarty.com/pp_editable_dropdown.html
if ((keycode>47 && keycode<59)||(keycode>62 && keycode<127) ||(keycode==32))
{
var vAllowableCharacter = "yes";
}
else
{
var vAllowableCharacter = "no";
}
//alert(window); alert(window.event);
if(getdropdown.options.length != 0)
// if dropdown is not empty
if (getdropdown.options.selectedIndex == (vEditableOptionIndex_A))
// if selected option the Editable option of the dropdown
{
// Empty space (ascii 32) is not captured by NetscapeFirefoxChrome when .text is used
// NetscapeFirefoxChrome removes extra spaces at end of string when .text is used
// NetscapeFirefoxChrome allows one empty space at end of string when .value is used
// Hence, use .value insead of .text
var vEditString = getdropdown[vEditableOptionIndex_A].value;
// make Editable option Null if it is being edited for the first time
if(vAllowableCharacter == "yes")
{
if ((getdropdown[vEditableOptionIndex_A].text == vEditableOptionText_A)||(getdropdown[vEditableOptionIndex_A].value == vEditableOptionText_A))
vEditString = "";
}
if (vAllowableCharacter == "yes")
// To handle addition of a character - source: http://chakrabarty.com/pp_editable_dropdown.html
{
vEditString+=String.fromCharCode(keycode);
// Concatenate Enter character to Editable string
// The following portion handles the "automatic Jump" bug
// The "automatic Jump" bug (Description):
// If a alphabet is entered (while editing)
// ...which is contained as a first character in one of the read-only options
// ..the focus automatically "jumps" to the read-only option
// (-- this is a common property of normal dropdowns
// ..but..is undesirable while editing).
var i=0;
var vEnteredChar = String.fromCharCode(keycode);
var vUpperCaseEnteredChar = vEnteredChar;
var vLowerCaseEnteredChar = vEnteredChar;
if(((keycode)>=97)&&((keycode)<=122))
// if vEnteredChar lowercase
vUpperCaseEnteredChar = String.fromCharCode(keycode - 32);
// This is UpperCase
if(((keycode)>=65)&&((keycode)<=90))
// if vEnteredChar is UpperCase
vLowerCaseEnteredChar = String.fromCharCode(keycode + 32);
// This is lowercase
if(e.which) //For NetscapeFirefoxChrome
{
// Compare the typed character (into the editable option)
// with the first character of all the other
// options (non-editable).
// To note if the jump to the non-editable option was due
// to a Manual click (i.e.,changed on purpose by user)
// or due to System properties of dropdown
// (i.e.,user did not change the option in the dropdown;
// instead an automatic jump happened due to inbuilt
// dropdown properties of browser on typing of a character )
for (i=0;i<=(getdropdown.options.length-1);i++)
{
if(i!=vEditableOptionIndex_A)
{
var vReadOnlyString = getdropdown[i].value;
var vFirstChar = vReadOnlyString.substring(0,1);
if((vFirstChar == vUpperCaseEnteredChar)||(vFirstChar == vLowerCaseEnteredChar))
{
vSelectChange_A = 'AUTO_SYSTEM';
// Indicates that the Change in dropdown selected
// option was due to System properties of dropdown
break;
}
else
{
vSelectChange_A = 'MANUAL_CLICK';
// Indicates that the Change in dropdown selected
// option was due to a Manual Click
}
}
}
}
}
// Set the new edited string into the Editable option
getdropdown.options[vEditableOptionIndex_A].text = vEditString;
getdropdown.options[vEditableOptionIndex_A].value = vEditString;
return false;
}
return true;
}
function fnKeyUpHandler_A(getdropdown, e)
{
fnSanityCheck_A(getdropdown);
if(e.which) // NetscapeFirefoxChrome
{
if(vSelectChange_A == 'AUTO_SYSTEM')
{
// if editable dropdown option jumped while editing
// (due to typing of a character which is the first character of some other option)
// then go back to the editable option.
getdropdown[(vEditableOptionIndex_A)].selected=true;
}
var vEventKeyCode = FindKeyCode(e);
// if [ <- ] or [ -> ] arrow keys are pressed, select the editable option
if((vEventKeyCode == 37)||(vEventKeyCode == 39))
{
getdropdown[vEditableOptionIndex_A].selected=true;
}
}
}
/*-------------------------------------------------------------------------------------------- source: http://chakrabarty.com/pp_editable_dropdown.html */
/***************************************************************
http://chakrabarty.com/pp_editable_dropdown.html
http://chakrabarty.com/combobox.html
***************************************************************/
</script> <!--end of script for dropdown lstDropDown_A -->
<!--******* End of "HEAD" (of HTML document) *******-->
</head>
<!--
************************************************************
************************************************************
STEP TWO: Copy the following code into
the BODY of your HTML document
************************************************************
************************************************************
-->
<!--******* Start of "BODY" (of HTML document) *******-->
<body>
<form name="frmName" method="post">
<div style="text-align:center;">
<hr>
<span style="color:red;font-weight:bold;">
<a href="http://chakrabarty.com/pp_editable_dropdown.html" target="_top" style="text-decoration:none;color:red;font-weight:bold;">COMBOBOX</a>
in
<a href="http://chakrabarty.com/pp_editable_dropdown.html" target="_top" style="text-decoration:none;color:red;font-weight:bold;">HTML</a>
:
<a href="http://chakrabarty.com/pp_editable_dropdown.html" target="_top" style="text-decoration:none;color:red;font-weight:bold;">Editable</a>
<a href="http://chakrabarty.com/pp_editable_dropdown.html" target="_top" style="text-decoration:none;color:red;font-weight:bold;">dropdown</a> /
<a href="http://chakrabarty.com/pp_editable_dropdown.html" target="_top" style="text-decoration:none;color:red;font-weight:bold;">listbox</a> --
with any one
<a href="http://chakrabarty.com/pp_editable_dropdown.html" target="_top" style="text-decoration:none;color:red;font-weight:bold;">select</a>
<a href="http://chakrabarty.com/pp_editable_dropdown.html" target="_top" style="text-decoration:none;color:red;font-weight:bold;">option</a>
as
<a href="http://chakrabarty.com/pp_editable_dropdown.html" target="_top" style="text-decoration:none;color:red;font-weight:bold;">editable</a>
(like a
<a href="http://chakrabarty.com/pp_editable_dropdown.html" target="_top" style="text-decoration:none;color:red;font-weight:bold;">textbox</a>
) and the rest as readonly. Uses
<a href="http://chakrabarty.com/pp_editable_dropdown.html" target="_top" style="text-decoration:none;color:red;font-weight:bold;">javascript</a>.
</span>
<hr>
<br>
The FIRST option ( default : " --?-- " ) is Editable !! ... type in whatever you want!
<br>
<br>
<select name="lstDropDown_A" id="lstDropDown_A" style="" onKeyDown="fnKeyDownHandler_A(this, event);" onKeyUp="fnKeyUpHandler_A(this, event); return false;" onKeyPress = "return fnKeyPressHandler_A(this, event);" onChange="fnChangeHandler_A(this, event);">
<option value="" style="font-family:Courier,monospace;color:#ff0000;background-color:#ffff00;">--?--</option> <!-- This is the Editable Option -->
<option>Editable Dropdown</option>
<option>Combobox</option>
<option>Tiger</option>
<option>Software</option>
<option>India</option>
</select>
<br>
<br>
Note: Your browser needs to have Javascript Scripting enabled.
<br>
<br>
For more information, please refer (and feel free to distribute the link):
<br>
<br>
<a href="http://chakrabarty.com/pp_editable_dropdown.html" style="text-decoration:none;color:blue;font-weight:bold;" target="_top">
http://chakrabarty.com/pp_editable_dropdown.html
</a>
<br>
<br>
<hr>
</div>
</form>
<!--******* End of "BODY" (of HTML document) *******-->
</body>
<!--******* End of "HTML" document *******-->
</html>