EDITABLE Dropdown (ListBox/ComboBox):

SCRIPT: First Option Editable

<!-- *************************************************************** Hi, I have written a set of javascript functions for "Editable Dropdowns"... 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 Netscape) 4.Editable Option: Press "BackSpace" to remove 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 famous "Backspace" bug or "automatic Jump" bug. 8.The characters to be allowed/disallowed in Editable Option can be customized. 9.Overcomes all the bugs I have come across in other logic/codes for Editable dropdowns. It works beautifully !!! These set of functions do NOT have the following bugs commonly associated with "Editable Drop-downs" : 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 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). 3. CAPS bug : Values Entered are always displayed in CAPS ....lower case not possible. 4. Javascript error when dropdown is empty and key is pressed. 5. Doesn't allow the certain special characters.. (this can be customized in my code) The new set of functions I have written do not have any of these bugs,also the various characters allowable for entry into Editable option..may be customized by minor modifications in the code (you need to know the keycode/ASCII value of the character to be allowed/disallowed). Hope you will find this code useful. THANKING YOU, WITH REGARDS, Subrata Chakrabarty. chakrabartys@yahoo.com --> <!-- *************************************************************** TWO STEPS TO INSTALL EDITABLE DROP DOWN - Subrata Chakrabarty.: 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 - Subrata Chakrabarty.: 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> <TITLE>Editable Menu - Subrata Chakrabarty</TITLE> <SCRIPT LANGUAGE="JavaScript"> //Common functions for all dropdowns /*---------------------------------------------- The Common function used for all dropdowns are: ----------------------------------------------- -- function fnKeyDownHandler(getdropdown, e) -- function fnLeftToRight(getdropdown) -- function fnRightToLeft(getdropdown) -- function fnDelete(getdropdown) -- function FindKeyCode(e) -- function FindKeyChar(e) -- function fnSanityCheck(getdropdown) --------------------------- Subrata Chakrabarty */ function fnKeyDownHandler(getdropdown, e) { fnSanityCheck(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 Netscape 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) { fnDelete(getdropdown); } // backspace key pressed if(vEventKeyCode == 8 || vEventKeyCode==127) { if(e.which) //Netscape { //e.which = ''; //this property has only a getter. } else //Internet Explorer { //To prevent backspace from activating the -Back- button of the browser e.keyCode = ''; if(window.event.keyCode) { window.event.keyCode = ''; } } return true; } // Tab key pressed, use code below to reorient to Left-To-Right flow, if needed //if(vEventKeyCode == 9) //{ // fnLeftToRight(getdropdown); //} } function fnLeftToRight(getdropdown) { getdropdown.style.direction = "ltr"; } function fnRightToLeft(getdropdown) { getdropdown.style.direction = "rtl"; } function fnDelete(getdropdown) { if(getdropdown.options.length != 0) // if dropdown is not empty { if (getdropdown.options.selectedIndex == vEditableOptionIndex_A) // if option the Editable field { getdropdown.options[getdropdown.options.selectedIndex].text = ''; //getdropdown.options[getdropdown.options.selectedIndex].value = ''; //Use this line only if want to change the internal value too; else this line is not required. } } } /* Since Internet Explorer and Netscape 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 Netscape), 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; //Netscape } 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; } function fnSanityCheck(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; } } </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 --------------------------- Subrata Chakrabarty */ /*---------------------------------------------- The dropdown specific functions (which manipulate dropdown specific global variables) used by all dropdowns are: ----------------------------------------------- 1) function fnChangeHandler_A(getdropdown) 2) function fnKeyPressHandler_A(getdropdown, e) 3) function fnKeyUpHandler_A(getdropdown, e) --------------------------- Subrata Chakrabarty */ /*------------------------------------------------ IMPORTANT: Global Variable required to be SET by programmer -------------------------- Subrata Chakrabarty */ 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 -------------------------- Subrata Chakrabarty */ 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 -------------------------- Subrata Chakrabarty */ function fnChangeHandler_A(getdropdown) { fnSanityCheck(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 - Subrata Chakrabarty { 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(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. // - Subrata Chakrabarty 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 { var vEditString = getdropdown[vEditableOptionIndex_A].text; // make Editable option Null if it is being edited for the first time if((vAllowableCharacter == "yes")||(keychar=="backspace")) { if (vEditString == vEditableOptionText_A) vEditString = ""; } if (keychar=="backspace") // To handle backspace - Subrata Chakrabarty { vEditString = vEditString.substring(0,vEditString.length-1); // Decrease length of string by one from right vSelectChange_A = 'MANUAL_CLICK'; // Indicates that the Change in dropdown selected // option was due to a Manual Click } //alert("EditString2:"+vEditString); if (vAllowableCharacter == "yes") // To handle addition of a character - Subrata Chakrabarty { 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 Netscape { // 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].text; 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; //Use this line only if want to change the internal value too; else this line is not required. return false; } return true; } function fnKeyUpHandler_A(getdropdown, e) { fnSanityCheck(getdropdown); if(e.which) // Netscape { 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; } } } /*-------------------------------------------------------------------------------------------- Subrata Chakrabarty */ </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"> <BR> <br> <br> Editable Dropdown: <br> <br> <SELECT name="lstDropDown_A" id="lstDropDown_A" style="" onKeyDown="fnKeyDownHandler(this, event);" onKeyUp="fnKeyUpHandler_A(this, event); return false;" onKeyPress = "return fnKeyPressHandler_A(this, event);" onChange="fnChangeHandler_A(this, event);"> <OPTION value="" style="COLOR:#ff0000;BACKGROUND-COLOR:#ffff00;">--?--</OPTION> <!-- This is the Editable Option --> <option>Subrata</option> <option>Chakrabarty</option> <option>Tiger</option> <option>Software</option> <option>India</option> </SELECT> <br> </FORM> <!--******* End of "BODY" (of HTML document) *******--> </BODY> <!--******* End of "HTML" document *******--> </HTML>

References

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Author: Subrata Chakrabarty

Declaration

I hereby declare that this document is based on my personal experiences and needs as a programmer. To the best of my knowledge, this document does not contain any material that infringes the copyrights of any other individual or organization.

I allow anyone interested to use the code or portions of the code (for the Editable dropdown/listbox/combobox), provided my name is retained as the "Author" of this code, and no attempt is made to hide my contribution as the developer of any portion of the code.

You may wish to integrate the code provided here with your desired needs, but kindly retain my name as the Author for the sections where my code (or significant portions of my code) is used.

Thanks

Subrata Chakrabarty.

chakrabartys@yahoo.com

Website:

http://www.geocities.com/chakrabartys/pp_editable_dropdown.html

Target readers :

Developers/Programmers

Keywords :

Editable,Edit,Dropdown,Listbox,Combobox

Technologies used: Javascript,HTML