Regular Expression to accept Alphanumeric Alphabets and Numbers and Space in TextBox in ASPNet

In this article I will explain with an example, how to use Regular Expression (Regex) to accept/allow Alphanumeric characters i.e. Alphabets (Upper and Lower case) and Numbers (Digits) and Space in TextBox in ASP.Net using:-

1. RegularExpression Validator.

2. JavaScript.

3. jQuery.

1. Regular Expression to accept Alphanumeric (Alphabets and Numbers) and Space in TextBox using RegularExpression Validator

The following HTML Markup consists of a TextBox, a Button and a RegularExpression Validator which has been applied with the Regular Expression (Regex) to accept only Alphanumeric characters i.e. Alphabets (Upper and Lower case) and Numbers (Digits) and Space as valid characters.

<asp:TextBox ID="TextBox1" runat="server" />

<br />

<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ControlToValidate="TextBox1"

ForeColor="Red" ValidationExpression="[a-zA-Z0-9\s]*$" ErrorMessage="Valid characters: Alphabets, Numbers and Space." />

<br />

<asp:Button ID="Button1" Text="Validate" runat="server" />

2. Regular Expression to accept Alphanumeric (Alphabets and Numbers) and Space in TextBox using JavaScript

The following HTML Markup consists of a TextBox, a Button and an HTML SPAN. On the OnClientClick event of the Button, a JavaScript function is executed which validates the TextBox text against the Regular Expression (Regex) and if it contains character other than Alphabets, Numbers or Space then an error message is displayed.

<asp:TextBox ID="TextBox2" runat="server" />

<br />

<span id="spnError" style="color: Red; display: none">Valid characters: Alphabets, Numbers

and Space.</span>

<br />

<asp:Button ID="Button2" Text="Validate" runat="server" CausesValidation="false"

OnClientClick="return Validate()" />

function Validate() {

var isValid = false;

var regex = /^[a-zA-Z0-9\s]*$/;

isValid = regex.test(document.getElementById("<%=TextBox2.ClientID %>").value);

document.getElementById("spnError").style.display = !isValid ? "block" : "none";

return isValid;

}

</script>

3. Regular Expression to accept Alphanumeric (Alphabets and Numbers) and Space in TextBox using jQuery

The following HTML Markup consists of a TextBox, a Button and an HTML SPAN. To the Button a jQuery click event handler is attached thus when the button is clicked, the TextBox text is validated against the Regular Expression (Regex) and if it contains character other than Alphabets, Numbers or Space then an error message is displayed.

<asp:TextBox ID="TextBox3" runat="server" />

<br />

<span id="spnError2" style="color: Red; display: none">*Valid characters: Alphabets,

Numbers and Space.</span>

<br />

<asp:Button ID="btnValidate" Text="Validate" runat="server" CausesValidation="false" />