change an string to number js code example
Example 1: javascript string to a decimal
<script language="JavaScript" type="text/javascript">
var a = "3.3445";
var c = parseFloat(a);
alert(c);
</script>
Example 2: convert a string to number in javascript
var x = parseInt("1000", 10); // you want to use radix 10
// so you get a decimal number even with a leading 0 and an old browser ([IE8, Firefox 20, Chrome 22 and older][1])