function cmail(field)
{
with (field)
{
apos=value.indexOf("@")
dotpos=value.lastIndexOf(".")
if (apos<1||dotpos-apos<2) 
  {return false}
else {return true}
}
}
	function isEmail(str) {
	      var supported = 0;
	   if (window.RegExp) {
	      var tempStr = "a";
	      var tempReg = new RegExp(tempStr);
	      if (tempReg.test(tempStr)) supported = 1;
	   }
	   if (!supported) {
	   return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
	   var r1 = new RegExp("(@.*@)|(\\.\\.)|(@\\.)|(^\\.)");
	   var r2 = new RegExp("^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$");
	   return (!r1.test(str) && r2.test(str));
	}
	}
	
	function setColor(el, bg) {
	   if (el.style) el.style.backgroundColor = bg;
	}
	
	function checkInput(form) {
	   var bgBad = "#ffff99";
	   var bgGood = "#ffffff";
	   valid = true;
	   	   }	
	   
	   
	   if (form.nama.value == "") {
		  valid = false;
	      setColor(form.nama, bgBad);
		  alert ("U heeft geen naam ingevuld.");
		  form.nama.focus();
	   	  return valid;
	   } else {
	      setColor(form.nama, bgGood);
	   }	   
	   
	   if (form.email.value == "") {
		  valid = false;
	      setColor(form.email, bgBad);
		  alert ("U heeft geen e-mail adres ingevuld.");
		  form.email.focus();
	   	  return valid;
	   } else {
	      if (cmail(form.email)) {
		     setColor(form.email, bgGood);
		  } else {
		  	valid = false;
		  	setColor(form.email, bgBad);
		  	alert ("Het ingevulde e-mail adres is ongeldig.");
			form.email.focus();
			return valid;
		  }
	   }
	   

}