validate and evaluate arithmetic expressions

Can any one help me with a good code in javascript to validate and evaluate the arithmetic expression entered in a text box item.
srividya_krisAsked:
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sureshkumarConnect With a Mentor Commented:
<html>
<head>
<script language="javascript">
function evaluate(form)
{
if(form.elements[0].value.length==0){
alert("sorry you have to enter expression");
}
form.elements[1].value=eval(form.elements[0].value);
}
</script>
</head>
<body>
<form>
<input type=text name=expre><br>
<input type=text name=value><br>
<input type=button value="click" onClick="evaluate(this.form)">
</form>
</body>
</html>

further queries
suresh kumar
0
 
xabiCommented:
Try this:

<html>
<head>
<script>
<!--
function errorHandler(message,url,line) {
  alert("Invalid expression")
  return true
}

function doit(idform) {
 eval ("idform.result.value = " + idform.expression.value)
}
window.onerror = errorHandler
//-->
</script>
</head>
<body>
<form name="myform">
Expression: <input type="text" name="expression"><br>
Result: <input type="text" name="result" readonly><br><br>
<input type="button" value="Evaluate" onclick="doit(this.form)">
</form>
</body>
</html>

xabi
0
 
xabiCommented:
sureshkumar:

It's nice to see a how someone cut and paste your code, change a little things and post it as a answer.

Question:

Where your code validate the expression?

xabi
0
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