How to add a string to another string in javascript code example

Example 1: string javascript concatenation

var dest = new String("");
    var src = new String("aze");
    var ar = new Array();
    ...
    ar.push(src);
    ar.push(src);
    ...
    dest = ar.join("");

Example 2: string javascript concatenation

var dest = new String("");
    var src = new String("aze");
    ...
    dest += src + src + src + src + src;