function validate (form_id,email)
{
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   var address = document.forms[form_id].elements[email].value;
   if(reg.test(address) == false) {
      alert('Email no válido');
      return false;
   }
}

function mouseOver (el)
{
	el.style.cursor = (navigator.appName == 'Microsoft Internet Explorer') ? 'hand' : 'pointer';
}