Answer:
Let's see an Simple example to understand.
Assuming that we have a Textbox and Button on the ASP.NET page like
below.
<asp:TextBox ID="txtName" runat="server"></asp:TextBox>
<asp:Button ID="btnSubmit" runat="server" Text="Submit"
OnClientClick="return validate()" />
Now, Add the below code snippet on the page source.
<script language="javascript" type="text/javascript">
function ValidateTextBox()
{
if(document.getElementById("<%=txtName.ClientID%>").value == "")
{
alert("Name Field Cannot be Empty");
document.getElementById("<%=txtName.ClientID%>").focus();
return false;
}
return true;
}
</script>
Once you have completed the above steps, just run the project and see the
result.
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Regards,