function checkLoginForm()
{
// defaults for the script
   var errors = '';
   var oMyForm = document.loginform;
// regular expression patterns
   var validemail     = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
   var validusername  = /^[a-zA-Z 0-9]{6,}$/;
   var validpassword  = /^[a-zA-Z 0-9]{6,}$/;

// test for basic mandatory form field values
   if(!validemail.test(oMyForm.c1_email.value))
   { errors+='Please type your email address\n'; }
   if(!validpassword.test(oMyForm.c1_pw.value))
   { errors+='Please type your password.\n'; }
// show errors or submit form
   if (errors){alert(errors);}
   else{oMyForm.submit();}
}