How to do required field validation on server side control using Client Validation in Asp.net

How to do required field validation on server side control using Client Validation in Asp.net

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Step 1: First open your website first where you want to implement client script

Step 2 : Open you .aspx page

Step 3 :  Create client script on page like below code


<script type="text/javascript">
    function ValidateRequiredField(objTextBox, errorControl) {
           if (objTextBox.value == "") {
                document.getElementById(errorControl).style.display = 'block';
            }
            else {
                document.getElementById(errorControl).style.display = 'none';
            }
        }

 </script>


Step 4 : Add textbox control on page .

Step 5 : Add one property client side property of control  onBlur and add below code

<asp:TextBox ID="txtNum2" runat="server"           onBlur="ValidateRequiredField(this,'requiredtxtNum2')"></asp:TextBox>
    <span id="requiredtxtNum2" style="color: Red; display: none">Please enter number 2 value</span>