How to extract special keys in javascript?

Question

I am calling .keyup function of Search Textbox, and in that keyup(), I am refreshing the GRID from the database.

Problem:

But the grid is getting refreshed for (special keys too ) arrow keys, number lock,function keys and all other keys and refreshing for those keys are unnecessary. Except backspace, return,tab,space,delete.

I want to construct a regular expression such that it filters out all the control keys.

Sample code:

$('#searchContent').keyup(function (e) {
    var key = e.which;
    if ( /*condition*/ ) {
        return;
    }
    //my code goes here...
}

What I have done:

Searched net thoroughly and I came up with hotkey, but that doesn't solved my purpose. So, any smart regular expression are there?

This answer may help: http://stackoverflow.com/questions/3977642/how-to-know-if-keyup-is-a-character-key-jquery — Matt Stone, Mar 22 '13 at 11:33
@EAGER_STUDENT Which keys DO need to trigger the grid refresh. — Mark Walters, Mar 22 '13 at 11:33
You could store the current value somewhere and then on each keystroke compare to the new value to see if it has changed... — nnnnnn, Mar 22 '13 at 11:34
@Mark Walters any alpha numeric, punctuation's, ctrl+v,shift+ins,and any keys that could possibly retrive differnt information from database. — Muthu Ganapathy Nathan, Mar 22 '13 at 11:40

rhughes · Answer 1 · 2013-03-22T12:17:33.840

0

Try this HTML to see which codes match up with which keys (taken from Mozilla):

<html>
<head>
    <title>charCode example</title>

    <script type="text/javascript">

        function showChar(e)
        {
            alert("Key Pressed: " + String.fromCharCode(e.charCode) + "\n"
                  + "charCode: " + e.charCode);
        }

        </script>
    </head>

    <body onkeypress="showChar(event);">
        <p>Press any 'character' type key.</p>
    </body>
</html>

edited Mar 22 '13 at 12:17

answered Mar 22 '13 at 11:34

rhughes

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2

But the `keypress` event as currently used in this answer may not trigger for delete or backspace... – nnnnnn Mar 22 '13 at 11:36
it will fail in chrome and id incase of delete or backspace – Arun P Johny Mar 22 '13 at 11:58

score 0 · Answer 2 · answered Mar 22 '13 at 15:01

Try this trick:

function checkForChanges(){
   var txt = $('#searchContent');
   if(txt.val() != txt.attr('xvalue') {
      //do referesh grid content here
   }
}

$('#searchContent').keyup(function (e) {
    $(this).attr('xvalue') = this.value;    
    clearTimeout(this.changeTimer);    
    this.changeTimer = setTimeout(checkForChanges, 20);
}

How to extract special keys in javascript?

2 Answers2