function bookmarksite() {
	if (document.all) { // Internet Explorer
		window.external.AddFavorite("http://www.ems-tracking.net", "EMS Tracking - EMS China");
	} else {
		alert("Please press Ctrl + D to save bookmark. Thank you very much for your support!");
	}
}
function checkdata() {
	var str = this.document.emstracking.number.value;
	var len = str.length;
	var i;
	var charnum = "0123456789";
	var charalpha = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
	var vericode = this.document.emstracking.vericode.value;
	if (vericode == "") {
		alert("Please input verification code.");
		return false;
	}
	if (str == "") {
		alert("Please input your EMS tracking number.");
		return false;
	} else if (len != 13) {
		alert("EMS tracking number should be 13 characters long. Please modify your input and re-submit.");
		return false;
	} else if ((charalpha.indexOf(str.substring(0,1)) == -1) || (charalpha.indexOf(str.substring(1,2)) == -1)) {
		alert("The first two characters of EMS tracking number should be alphabets. Please modify your input and re-submit.");
		return false;
	} else if ((charalpha.indexOf(str.substring(11,12)) == -1) || (charalpha.indexOf(str.substring(12,13)) == -1)) {
		alert("The last two characters of EMS tracking number should be alphabets. Please modify your input and re-submit.");
		return false;
	}
	for (i=2;i<11;i++) {
		if (charnum.indexOf(str.substring(i,i+1),0) == -1) {
			alert("The 3rd to 11th characters of EMS tracking number should be digits. Please modify your input and re-submit.");
			return false;
		}
	}
	this.document.emstracking.action = "http://www.ems-tracking.net/single-ems-tracking.php?number=" + str;
	return true;
}