function trim(str) {
	return str.replace(/^\s+|\s+$/g, '');
}

function isEmail(emailStr) {
   var emailReg = /^[a-zA-Z0-9_\-\.]+@([a-zA-Z0-9.-]+\.)+[a-zA-Z0-9.-]{2,4}$/;
   var regex = new RegExp(emailReg);
   return regex.test(emailStr)
}