function checkEmailFormat(s) {
	var chrs = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-@';
	var sLen = s.length; var i=0, c=0, cCnt=0, step=0;
	if (sLen < 6) return false;
	while (i < sLen){
		c=s.charAt(i);
		if (!(chrs.indexOf(c)>=0 || (c=='_' && step<1))) return false;
		if (c=='.') { if (cCnt<1) return false; cCnt=0; }
		if (c=='@') { if (step>0) return false; if (cCnt<1) return false; step++; cCnt=0; }
		cCnt=cCnt+1; i++;
	}	
	if (cCnt < 3 || cCnt > 5 || step==0 || (s.indexOf(".")<0))
		return false;
	
	var temp = s.split('@');
	fullDomain = temp[1];
	temp = fullDomain.split('.');
	partDomain = temp[0];

	return true;
}