AutoSearch SELECT tag

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Introduction

If you spend any time surfing the web you will find <select> lists. In all cases I've encountered the default single character searches are used to help you "quickly" find the list item you want. As an example, to reach North Carolina in a list of states you would type "N" which takes you to Nebraska. "O" will take you to Ohio, so you will quickly learn to type "N" and down arrow 6 times to get "North Carolina".

I think we can do better.

An auto searching <select> list would allow us to type "No" and automatically get "North Carolina". Mississippi and Arkansas are other good examples. A few lines of client side JavaScript can solve this nuisance. I've included examples of both types of <select> lists for USA states below so give them a try.

Standard Non Searching Select List

AutoSearching Select List

How it works

Basically the javascript code driving the AutoSearching <select> above records each keystroke in a hidden input tag and uses ALL keystrokes to search for a matching Option in the list. A few questions may come to mind, such as "How to you clear previously captured keystrokes?". The onBlur() and onFocus() events clear previous keystrokes but what about starting a new search without moving focus from the <select> list?. In this case I used the Delete key. I decided not to use BackSpace key for this since many browsers use BackSpace to navigate Back.

How to use AutoSearch <select>

First, add selectKeyDown(), selectKeyPress(), and clr() javascript functions to your page as found in the source code download, or simply View->Source for this page.

Next, add onBlur(), onFocus(), onKeyPress(), and onKeyDown() event handlers to your <select> tags

Last, add a hidden input tag named "keys" to store the previous keystrokes

A little debugging in case you are an occasional fumble finger typist like me and your <select> tags will never be the same.

The Code

// Java Script to Handle AutoSearch

function selectKeyDown()
{
    // Delete Key resets previous search keys

    if(window.event.keyCode == 46)
        clr();
}
function selectKeyPress()
{
    // Notes:

    //    1) previous keys are cleared onBlur/onFocus and with Delete key

    //    2) if the search doesn't find a match, this returns to normal 1 key 

    //        search setting returnValue = false below for ALL cases will 

    //        prevent default behavior

    
    //TODO:

    //    1) add Netscape handling

    

    var sndr = window.event.srcElement;
    var pre = this.document.all["keys"].value;
    var key = window.event.keyCode;
    var char = String.fromCharCode(key);

    // "i" -> ignoreCase

    var re = new RegExp("^" + pre + char, "i"); 

    for(var i=0; i<sndr.options.length; i++)
    {
        if(re.test(sndr.options[i].text))
        {
            sndr.options[i].selected=true;
            document.all["keys"].value += char;
            window.event.returnValue = false;
            break;
        }
    }
}
function clr()
{
    document.all["keys"].value = "";
}

Tested Browsers

1. Internet Explorer 6.0.2800
2. Mozilla 1.2.1

TODO

1. Add Netscape Navigator handling.
2. Test other and older browsers.
3. Let me here your comments on this.

History

Release 03/02/2003