Change Username form an Array's data to another Array's data

usernameE2C.js

//========== method 1 ==========
var Ename = array("Aname", "Bname", "Cname", "Dname");
var Cname = array("A名", "B名", "C名", "D名");
function usernameE2C1(urn, eArray, cArray) {
	if(eArray == undefined) eArray = Ename;
	if(cArray == undefined) cArray = Cname;
	if(eArray.length != cArray.length) return "";
	
	for(var i = 0; i <= eArray.length; i++)
		if(eArray[i] == urn)
			return cArray[i];
}
var username1 = usernameE2C1(prefix.nick);
//========== method 2 ==========
var names = [
	{"E":"Aname", "C":"A名"},
	{"E":"Bname", "C":"B名"},
	{"E":"Cname", "C":"C名"},
	{"E":"Dname", "C":"D名"}
];
function usernameE2C2(urn) {
	for(var k in names)
		if(names[k].E == urn)
			return names[k].C;
	return "";
}
var username2 = usernameE2C2(prefix.nick);