JS删除数组里的某个元素实例代码

Array.prototype.indexOf = function(val) { 
for (var i = 0; i < this.length; i++) { 
if (this[i] == val) return i; 
} 
return -1; 
};

Array.prototype.remove = function(val) { 
var index = this.indexOf(val); 
if (index > -1) { 
this.splice(index, 1); 
} 
};

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

emp.remove('fd');

//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']

//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

var arr = ['a','b','c','d']; 
arr.splice(1,0,'ttt'); 
console.log(arr);   
//[&#39;a&#39;,&#39;ttt&#39;,&#39;b&#39;,&#39;c&#39;,&#39;d&#39;] 表示在下标为1处添加一项&#39;ttt&#39;<span style="font-size:14px;font-family:Arial, Helvetica, sans-serif;background-color:rgb(255,255,255);"> </span>

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