JavaScript to validate Price input into a TextBox

Guys, first time in my life I am writing JavaScript for one of my project. I need a client side validation for an input into asp:TextBox.

I wrote a JavaScript function that would, actually, take whole element as object and use a regex to match the input with a pattern.

I learned that we don’t need to create an object of a RegEx() as we do in C#.

A “var” variable has “match” function that will use regex pattern to match the input.

Below is the javascript function that I wrote to validate my input.

<script language="javascript">     function validatePrice(textBoxId) {         var textVal = textBoxId.value;         var regex = /^(\$|)([1-9]\d{0,2}(\,\d{3})*|([1-9]\d*))(\.\d{2})?$/;         var passed = textVal.match(regex);         if (passed == null) {             alert("Enter price only. For example: 523.36 or $523.36");             textBoxId.Value = "";         }     } </script>

I wanted to fire the validation after I lost a focus on text box. To achieve this I did Google and went through all Form, Window etc type of event described at http://www.w3schools.com/tags/ref_eventattributes.asp . I used “onblur” event which is as same as OnLostFocus() in most of the WinForm controls.

<asp:TextBox ID="TextBox19" runat="server" Visible="False" Width="183px"       onblur="javascript:return validatePrice(this);"></asp:TextBox>

This is my first javascript function. There may be best chance to improvise it. Please post your comments with changes.

Thanks & Enjoy!