js数组合并

    // 第一种
    var mergeTo = [4,5,6],
          mergeFrom = [7,8,9];  

    mergeTo = mergeTo.concat(mergeFrom);
    mergeTo; // is: [4, 5, 6, 7, 8, 9]  

    or
    var a = [1,2], b = [3,4], c = a.concat(b);  

    // 第二种
    var mergeTo = [4,5,6],
    var mergeFrom = [7,8,9];  

    Array.prototype.push.apply(mergeTo, mergeFrom);  

    mergeTo; // is: [4, 5, 6, 7, 8, 9]