String.prototype.trim = _trim;

function _trim()
{
var start = 0;
var end = 1;

 while(this.charAt(start) == " ") start++;
 while(this.charAt(this.length - end) == " ") end++;
 if (this.length == (end-1)) {
   return "";
 } else {
   return this.substring(start, this.length - end + 1);
 }
}

missings = new Array();
missings['geen_emailadres'] = 'U heeft geen email adres ingevuld.';
missings['geen_geldig_emailadres'] = 'Het ingevulde email adres is geen geldig email adres.';
missings['ongeldige_tekens_voor'] = 'Het emailadres bevat ongeldige tekens voor de @.';
missings['ongeldige_tekens_na'] = 'Het emailadres bevat ongeldige tekens na de @.';

function emailCheck (obj) {
emailObj=obj;
emailStr = emailObj.value;
if(emailStr == "")
{
    alert ( missings['geen_emailadres'] );
    return false;
}
var checkTLD=0;
var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
var emailPat=/^(.+)@(.+)$/;
var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
var validChars="\[^\\s" + specialChars + "\]";
var quotedUser="(\"[^\"]*\")";
var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
var atom=validChars + '+';
var word="(" + atom + "|" + quotedUser + ")";
var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
var matchArray=emailStr.match(emailPat);
if (matchArray==null) {
alert(missings['geen_geldig_emailadres']);
return false;
}
var user=matchArray[1];
var domain=matchArray[2];
for (i=0; i<user.length; i++) {
if (user.charCodeAt(i)>127) {
alert(missings['ongeldige_tekens_voor']);
return false;
}
}
for (i=0; i<domain.length; i++) {
if (domain.charCodeAt(i)>127) {
alert(missings['ongeldige_tekens_na']);
return false;
}
}
if (user.match(userPat)==null) {
alert(missings['geen_geldig_emailadres']);
return false;
}
/*
var IPArray=domain.match(ipDomainPat);
if (IPArray!=null) {
for (var i=1;i<=4;i++) {
if (IPArray[i]>255) {
alert("Het IP adres klopt niet.");
return false;
}
}
return true;
}
*/
var atomPat=new RegExp("^" + atom + "$");
var domArr=domain.split(".");
var len=domArr.length;
for (i=0;i<len;i++) {
if (domArr[i].search(atomPat)==-1) {
alert(missings['geen_geldig_emailadres']);
return false;
}
}
if (checkTLD && domArr[domArr.length-1].length!=2 &&
domArr[domArr.length-1].search(knownDomsPat)==-1) {
alert(missings['geen_geldig_emailadres']);
return false;
}
if (len<2) {
alert(missings['geen_geldig_emailadres']);
return false;
}
return true
}