How to validate for numbers only in textbox using Javascript

[Dhanisha K P]

In ASP.NET you can use textboxes that can enter only numbers. For this, first you have to create a javascript file.

For creating a javascript file,
first right click on the Project name in Solution Explorer
Then,
select Add New Item -> JScript File-> Ok

If you want, you can give a name to JSCript file. Here I use the name "number.js" . After that write the following code in that file.

function numberonly(e)
{
    var KeyID = (window.event) ? event.keyCode : e.which; 
    if(KeyID>=48 && KeyID<=57)
        return true;
    else
        alert("Please Enter Number Only");
        return false;
 }

Save this file. Take the source part of the webform. Add the following code in <head> of html.

<head>
<script type="text/javascript" src="number.js">
</script>
</head>

Take the source aspx.cs file. Inside the Page_Load function
write the below code.

TextBox1.Attributes.Add("onkeypress", "return numberonly(event);");

Where TextBox1 is the name of the TextBox where we want to enter the data.