function validateForm() { 
if (document.forms["MyForm"]["first_name"].value=="")
{ 
alert("Please enter your first name then re-submit this form."); 
return false; 
} 
if (document.forms["MyForm"]["last_name"].value=="")
{ 
alert("Please enter your last name then re-submit this form."); 
return false; 
} 
if (document.forms["MyForm"]["company"].value=="")
{ 
alert("Please enter your company name then re-submit this form."); 
return false; 
} 
if (document.forms["MyForm"]["email"].value=="")
{ 
alert("Please enter your e-mail then re-submit this form."); 
return false; 
} 
}