Numeric Number Only TextBox JavaScript RegularExpression Validator

In this example i am explaining how to create Numeric Number Only Textbox Using JavaScript Or Regular Expression Validator which accept only numbers in asp.net web page.

1. Number only textbox using javascript.

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Go to html source of aspx page and write below mentioned script in head section of page.

1<script type="text/javascript">

2function numberOnlyExample()

3{

4    if ((event.keyCode < 48) || (event.keyCode > 57))

5    return false;

6}

7</script>

Call this function in onKeyPress event of textbox. 
Write this code in html source of textbox.

<asp:TextBox ID="TextBox2" runat="server" 
             onKeyPress="return numberOnlyExample();">
</asp:TextBox>

We can also do this programmetically in code behind like this.

on Page_Load event of page add onKeyPress attribute to textbox and call the function to accept only numerics.

1protected void Page_Load(object sender, EventArgs e)

2    {

3       TextBox2.Attributes.Add("onkeypress", "return ((window.event.keyCode >= 48 && window.event.keyCode <= 58))");

4    }

2. Creating Numeric or Number only textbox using Regular Expression Validator.

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Drag and place RegularExpressionValidator control on aspx page and set it's properties as mentioned below in html code.

Set ControlToValidate property to textbox1.
Set ValidationExpression.
Set ErrorMessage.

HTML Source

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<asp:RegularExpressionValidator 
     ID="RegularExpressionValidator1" 
     runat="server" 
     ControlToValidate="TextBox1"
     ErrorMessage="Please Enter only Numbers" 
     ValidationExpression="\d+">
</asp:RegularExpressionValidator>