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javascript - problem in addEventListener for keypress event... for restricting the input charcters only - Stack Overflow

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I have placed one textbox.... I want to put restriction on it ..

that digits and special characters should not be allowed to input in textbox...

how can i do using onkeypress event in Javascript ???

my code is ...

<script>

 function event()
 {
    document.getElementById("TX1").addEventListener("keypress", handleKeyPress, false);


 }


function handleKeyPress(e)
{
    var restricted = "0123456789_#!";
    var key = e.keyCode || e.which;
    var i=0;
    for(;i<restricted.length;i++)
    {
      if (restricted.charCodeAt(i) == key) 
      {
        e.returnValue = false;

      }

         return true;
}

</script>

<body onLoad="event();">

<input type="text" name="T1" id="TX1" size="27" maxlength="35" >

</body>

I have placed one textbox.... I want to put restriction on it ..

that digits and special characters should not be allowed to input in textbox...

how can i do using onkeypress event in Javascript ???

my code is ...

<script>

 function event()
 {
    document.getElementById("TX1").addEventListener("keypress", handleKeyPress, false);


 }


function handleKeyPress(e)
{
    var restricted = "0123456789_#!";
    var key = e.keyCode || e.which;
    var i=0;
    for(;i<restricted.length;i++)
    {
      if (restricted.charCodeAt(i) == key) 
      {
        e.returnValue = false;

      }

         return true;
}

</script>

<body onLoad="event();">

<input type="text" name="T1" id="TX1" size="27" maxlength="35" >

</body>
Share edited Mar 13, 2011 at 10:09 Sarfraz 383k82 gold badges559 silver badges612 bronze badges asked Mar 13, 2011 at 10:08 hiren gamithiren gamit 2,1636 gold badges25 silver badges23 bronze badges
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2 Answers 2

Reset to default 5

that digits and special characters should not be allowed to input in textbox...

Don't do this through keypress filtering. It's user-hostile, confusing, messes up other control keypresses and is easy to defeat by using other methods of input, such as copy/paste, drag/drop, form fillers, spellcheckers, IMEs...

Instead, have a warning that visibly directs the user when they've put something unexpected in, eg.:

<input type="text" name="T1" id="TX1"/>
<div id="TX1_help">
    Please do not use numbers or ‘!’, ‘_’ or ‘#’ characters in this field.
</div>

<script type="text/javascript">
    var tx1= document.getElementById('TX1');
    var tx1help= document.getElementById('TX1_help');

    function checkTX1() {
        var isok= /^[^0-9_#!]*$/.test(tx1.value);
        tx1help.style.display= isok? 'none' : 'block';
    }
    checkTX1();

    // Re-check the field every time a key is pressed or other change event.
    // To ensure it is still checked in a timely fashion in the case of
    // non-keyboard events, add a timer as well.
    //
    tx1.onchange=tx1.onkeyup= checkTX1;
    setInterval(checkTX1, 500);
</script>

You can use addEventListener for the event attachment if you want to, but be aware this won't work in IE<9, for which you would need the attachEvent model. (event.returnValue is specific to the IE attachEvent model and will not work with addEventListener, which uses event.preventDefault() instead.)

Try the following:

document.getElementById('TX1').addEventListener('keypress', function(event) {
        if (event.keyCode == 13) {
        handleKeyPress();
    }
}); 

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