js向一维数组第一位插入一个字符串
例：
<script>
var arr = ["aaaaaa", "bbbbbbb", "ccccccc", "dddddd"];arr.splice(0,0,"aspbc.com");
console.log(arr);
</script>
输出的结果是：["aspbc.com", "aaaaaa", "bbbbbbb", "ccccccc", "dddddd"]
arr.splice(0,0,"aspbc.com");
console.log(arr);
</script>
输出的结果是：["aspbc.com", "aaaaaa", "bbbbbbb", "ccccccc", "dddddd"]