Form validation using javascript in asp.net
Javascript validation summary
Note: in master pages document.forms[0] will not work use document.getElementById(‘<%=txtFirstName.ClientID %>’);
<asp:Content ID=”Content1″ ContentPlaceHolderID=”head” Runat=”Server”>
<style type=”text/css”>
.style3
{
width: 138px;
}
</style>
<script type=”text/javascript”>
function valSubmit() {
var msg = “”;
var msg = “”;
var fName=document.getElementById(’<%=txtFirstName.ClientID%>’);
var lName=document.getElementById(’<%=txtLastName.ClientID%>’);
if ( fName.value == “”) {
msg += “- First Name” + “\n”;
}
if (lName.value == “”) {
msg += “- Last Name” + “\n”;
}
if (msg == “”) {
} else {
var valMsg1 = “The following required fields are missing.”;
var valMsg2 = “Please complete and resubmit.”
alert(valMsg1 + “\n\n” + valMsg2 + “\n\n” + msg);
return false;
} }
</script>
<div>
FirstName:<asp:TextBox ID=”txtFirstName” runat=”server”></asp:TextBox>
LastName:<asp:TextBox ID=”txtLastName” runat=”server”></asp:TextBox>
<asp:Button ID=”btnSubmit” runat=”server” Text=”Button” OnClientClick=”valSubmit()” />
</div>
</asp:Content>
Another Method for calling javascript: you can call OnClientClick=”valSubmit()” in Page_Load event like below code
protected void Page_Load(object sender, EventArgs e)
{
butSubmit.Attributes.Add(”onClick“, “return valSubmit();”);
}
Note: Return false is to stop post back when we click alert dialog box ok button
