1

2

3

4

5

6

Array.prototype.indexOf = function(val) {

for (var i = 0; i < this.length; i++) {

if (this[i] == val) return i;

}

return -1;

};

1

2

3

4

5

6

Array.prototype.remove = function(val) {

var index = this.indexOf(val);

if (index > -1) {

this.splice(index, 1);

}

};

1

var emp = ['abs','dsf','sdf','fd']

1

emp.remove('fd');

1

2

3

4

5

6

7

8

9

10

//删除起始下标为1，长度为1的一个值(len设置1，如果为0，则数组不变)

var arr = ['a','b','c','d'];

arr.splice(1,1);

console.log(arr);

//['a','c','d'];

//删除起始下标为1，长度为2的一个值(len设置2)

var arr2 = ['a','b','c','d']

arr2.splice(1,2);

console.log(arr2);

//['a','d']

1

2

3

4

5

6

7

8

9

//替换起始下标为1，长度为1的一个值为‘ttt'，len设置的1

var arr = ['a','b','c','d'];

arr.splice(1,1,'ttt');

console.log(arr);

//['a','ttt','c','d']

var arr2 = ['a','b','c','d'];

arr2.splice(1,2,'ttt');

console.log(arr2);

//['a','ttt','d'] 替换起始下标为1，长度为2的两个值为‘ttt'，len设置的1

1

2

3

4

var arr = ['a','b','c','d'];

arr.splice(1,0,'ttt');

console.log(arr);

//['a','ttt','b','c','d'] 表示在下标为1处添加一项'ttt'

1

2

3

4

var arr = ['a','b','c','d'];

delete arr[1];

arr;

//["a", undefined × 1, "c", "d"] 中间出现两个逗号，数组长度不变，有一项为undefined