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JavaScript to judge a simple example of a non-numeric

Source: Internet
Author: User
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This article introduces a simple example of JavaScript judging Non-numeric, and a friend in need can refer to the copy code code as follows:


<title> Determine whether it is a number and a space </title>
<script type= "text/ JavaScript "src=" jquery.min.js ></script>//There is no matter whether there is no
<script type= "Text/javascript"
function Check_num ()  //Create functions
{
    var num=document.getelementbyid ("num") .value; // Get Value (id=num)
    if (isNaN (num) | | num== "" | | Num.substring (0,0) ==0)   //Note the SUBSTRING function is used to determine the space
    { 
         alert ("Do not enter non-digital");
        return false;
   }else{
        alert ("correct");
   }
}
</script>
<body>
Please enter a number: <input type= "text" id= "num" name= "num" value = "" "
<input type=" Submit "  value=" submitted "o~n~c~l~i~c~k~=" Check_num ">//This is actually onclick but not write
</ Body>

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