Apply Client side Validatioin using javaScript in Asp.Net


step 1:- Put bellow javascript  code in .aspx page 

<script type="text/jscript">


function valddata()
{
if (document.getElementById("<%=ddlCluster.ClientID%>").value == "" || document.getElementById("<%=ddlCluster.ClientID%>").value == "0")
{
alert("Please Select Cluster");
document.getElementById("<%=ddlCluster.ClientID%>").focus();
return false;
}
else if (document.getElementById("<%=ddlTown.ClientID%>").value == "" || document.getElementById("<%=ddlTown.ClientID%>").value == "0")
{
alert("Please Select Town ");
document.getElementById("<%=ddlTown.ClientID%>").focus();
return false;
}
else if (document.getElementById("<%=ddlFeeder.ClientID%>").value == "" || document.getElementById("<%=ddlFeeder.ClientID%>").value == "0")
 {
alert("Please Select Feeder");
document.getElementById("<%=ddlFeeder.ClientID%>").focus();
return false;
}
else if (document.getElementById("<%=tCategory.ClientID%>").value == "<-Select->" || document.getElementById("<%=tCategory.ClientID%>").value == "0")
{
alert("Please Select Category");
document.getElementById("<%=tCategory.ClientID%>").focus();
return false;
}
else if (document.getElementById("<%=tActivity.ClientID%>").value == "Select Activity" || document.getElementById("<%=tActivity.ClientID%>").value == "0") {
alert("Please Select Activity");
document.getElementById("<%=tActivity.ClientID%>").focus();
return false;
}
else if (document.getElementById("<%=ddlSS.ClientID%>").value == "" || document.getElementById("<%=ddlSS.ClientID%>").value == "0")
{
alert("Please Select SubStation");
document.getElementById("<%=ddlSS.ClientID%>").focus();
return false;
}
else if (document.getElementById("<%=ddlFeeder.ClientID%>").value == "" || document.getElementById("<%=ddlFeeder.ClientID%>").value == "0")
{
alert("Please Select Feeder");
document.getElementById("<%=ddlFeeder.ClientID%>").focus();
return false;
}


else if (document.getElementById("<%=ddlRiskLevel.ClientID%>").value == "" || document.getElementById("<%=ddlRiskLevel.ClientID%>").value == "0")
 {
alert("Please Select Risk Level");
document.getElementById("<%=ddlRiskLevel.ClientID%>").focus();
return false;
}


else if (document.getElementById("<%=ddlRiskType.ClientID%>").value == "-Select risk Type-" || document.getElementById("<%=ddlRiskType.ClientID%>").value == "0")
 {
alert("Please Select Risk Type");
document.getElementById("<%=ddlRiskType.ClientID%>").focus();
return false;
}


else if (document.getElementById("<%=tTeamMember.ClientID%>").value == "" )
{
alert("Please Enter Name of PMC Person !");
document.getElementById("<%=tTeamMember.ClientID%>").focus();
return false;
}

else if (document.getElementById("<%=tDesignation.ClientID%>").value == "") {
alert("Please Enter Designation!");
document.getElementById("<%=tDesignation.ClientID%>").focus();
return false;
}

else if (document.getElementById("<%=ttkcperson.ClientID%>").value == "")
 {
alert("Please Enter Name of TKC Person !");
document.getElementById("<%=ttkcperson.ClientID%>").focus();
return false;
}
else if (document.getElementById("<%=txtObservations.ClientID%>").value == "")
{
alert("Please Enter Observations !");
document.getElementById("<%=txtObservations.ClientID%>").focus();
return false;
}
else
{
             return true;
}
}

</script>




Step 2:- Now Call javaScript Validation Function on submit button like this

<asp:Button ID="btnSubmit" OnClientClick="return valddata()" runat="server" OnClick="btnSubmit_Click" Text="Submit" ValidationGroup="valgrp" />