Restricting input to textbox: allowing only number-第5页回答

2楼-- · 2019-01-02 15:43

<input type="text" onkeypress="return isNumberKey(event,this)">

<script>
   function isNumberKey(evt, obj) {

            var charCode = (evt.which) ? evt.which : event.keyCode
            var value = obj.value;
            var dotcontains = value.indexOf(".") != -1;
            if (dotcontains)
                if (charCode == 46) return false;
            if (charCode == 46) return true;
            if (charCode > 31 && (charCode < 48 || charCode > 57))
                return false;
            return true;
        }


</script>

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十年一品温如言

3楼-- · 2019-01-02 15:43

The accepted solution is not complete, since you can enter multiple '.', for example 24....22..22. with some small modifications it will work as intended:

<HTML><HEAD>
<script type="text/javascript">

 function isNumberKey(txt, evt) {

    var charCode = (evt.which) ? evt.which : evt.keyCode;
    if (charCode == 46) {
        //Check if the text already contains the . character
        if (txt.value.indexOf('.') === -1) {
            return true;
        } else {
            return false;
        }
    } else {
        if (charCode > 31
             && (charCode < 48 || charCode > 57))
            return false;
    }
    return true;
}

</SCRIPT></HEAD><BODY>
<input type="text" onkeypress="return isNumberKey(this, event);" /> </BODY></HTML>

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余欢

4楼-- · 2019-01-02 15:44

Better solution

var checkfloats = function(event){
    var charCode = (event.which) ? event.which : event.keyCode;
    if (charCode != 46 && charCode > 31 && (charCode < 48 || charCode > 57))
        return false;

    if(event.target.value.indexOf('.') >=0 && charCode == 46)
        return false;

    return true;
}

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柔情千种

5楼-- · 2019-01-02 15:45

A small correction to @rebisco's brilliant answer to validate the decimal perfectly.

function isNumberKey(evt) {
    debugger;
    var charCode = (evt.which) ? evt.which : event.keyCode;
    if (charCode == 46 && evt.srcElement.value.split('.').length>1) {
        return false;
    }
    if (charCode != 46 && charCode > 31 && (charCode < 48 || charCode > 57))
        return false;
    return true;
}

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人气声优

6楼-- · 2019-01-02 15:46

If you want it for float values,

Here is the function I am using

<HTML>

<HEAD>
  <SCRIPT language=Javascript>
    <!--
    function check(e, value) {
      //Check Charater
      var unicode = e.charCode ? e.charCode : e.keyCode;
      if (value.indexOf(".") != -1)
        if (unicode == 46) return false;
      if (unicode != 8)
        if ((unicode < 48 || unicode > 57) && unicode != 46) return false;
    }
    //-->
  </SCRIPT>
</HEAD>

<BODY>
  <INPUT id="txtChar" onkeypress="return check(event,value)" type="text" name="txtChar">
</BODY>

</HTML>

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深知你不懂我心

7楼-- · 2019-01-02 15:46

I observed that for all the answers provided here, the things are not working if we select some portion of the text in textbox and try to overwrite that part. So I modified the function which is as below:

    <HTML>
  <HEAD>
    <SCRIPT language=Javascript>
       <!--
       function isNumberKey(evt)
       {
         var charCode = (evt.which) ? evt.which : event.keyCode;

if (charCode != 46 && charCode > 31 && (charCode < 48 || charCode > 57))
{
        return false;
}
 if (charCode == 46 && evt.srcElement.value.split('.').length>1 )
    {

        return false;

    } 

 if(evt.srcElement.selectionStart<evt.srcElement.selectionEnd)
    {
          return true;
    }

  if(evt.srcElement.value.split('.').length>1 && evt.srcElement.value.split('.')[1].length==2)
  {

     return false;
  }


    return true;
       }


       //-->
    </SCRIPT>
  </HEAD>
  <BODY>
    <INPUT id="txtChar" onkeypress="return isNumberKey(event)" 
           type="text" name="txtChar">
  </BODY>
</HTML>

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Restricting input to textbox: allowing only number

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