JavaScript数组在指定某个元素前或后添加元素

//原数组
var s = [[\'g\',\'g\'],[\'h\',\'h\'],[\'i\',\'i\']];
//要添加的元素
var s1 = [\'a\',\'b\',\'c\'];
//要添加的元素
var s2 = [\'d\',\'e\',\'f\'];
//向[\'g\',\'g\']前面添加元素
s.splice(0,0,s1);
//[\'g\',\'g\']后面添加元素
s.splice(2,0,s2);
console.log(s)

结果
未添加前
0: (2) ["g", "g"]
1: (2) ["h", "h"]
2: (2) ["i", "i"]

添加后
0: (3) ["a", "b", "c"]
1: (2) ["g", "g"]
2: (3) ["d", "e", "f"]
3: (2) ["h", "h"]
4: (2) ["i", "i"]