function ValidateForm()
{
    var str 
    str =""
    if(document.getElementById("txtFirstName").value == "") str = str+ "Enter First Name\n\ "
    if(document.getElementById("txtLastName").value == "") str = str + "Enter Last Name\n\ "
    if(document.getElementById("txtEmail").value == "") str = str + "Enter Email Address\n\ "
    if(document.getElementById("txtPhone").value == "") str = str + "Enter Phone Number\n\ "
    if(document.getElementById("txtZipCode").value == "") str = str + "Enter Zip Code\n\ "
       
    if (str != "")
    {
         alert(str); 
         return false;
    }
             
    return true;
}