//onsubmit="javascript:return validEmail('form_id','email');"
//validate email form
function validEmail(form_id,fieldname) {
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   var fieldresult = document.forms[form_id].elements[fieldname].value;
   if(reg.test(fieldresult) == false) {
      alert('Invalid Email Address');
      return false;
   }
}

function validName(form_id,fieldname) {
   var reg = /^\w+$/;
   var address = document.forms[form_id].elements[fieldname].value;
   if(reg.test(fieldresult) == false) {
      alert('Invalid Name');
      return false;
   }
}

function validAge(form_id,fieldname) {
   var reg = /^\d+$/;
   var address = document.forms[form_id].elements[fieldname].value;
   if(reg.test(fieldresult) == false) {
      alert('Invalid Age');
      return false;
   }
}

function validNumber(form_id,fieldname) {
   var reg = /^\d{10}$/;
   var address = document.forms[form_id].elements[fieldname].value;
   if(reg.test(fieldresult) == false) {
      alert('Invalid Telephone Number. Enter only numbers.');
      return false;
   }
}