var array = [0,1,2,3,4,5];
var index = array.indexOf(5);

if (index > -1) {
? ? array.splice(index, 1);
}

var colors = ["red", "blue", "grey"]; ? //創(chuàng)建一個(gè)包含3個(gè)字符串的數(shù)組
colors.length = 2;
console.log(colors[2]); ?//undefined

var arr = [1, 2, 3, 4];
delete arr[0];
console.log(arr); ? //[undefined, 2, 3, 4]

var colors = ["red", "blue", "grey"];
var item = colors.pop();
console.log(item); ? ? ?//"grey"
console.log(colors.length); ? ?//2

var colors = ["red", "blue", "grey"];
var item = colors.shift();
console.log(item); ? ? ?//"red"
console.log(colors.length); ? ?//2

var colors = ["red", "blue", "grey"];
var item = colors.splice(0, 1);
console.log(item); ? ? ?//"red"
console.log(colors); ? ?//["blue", "grey"]

var colors = ["red", "blue", "grey"];
colors.forEach(function(item, index, arr) {
? ? if(item == "red") {
? ? ? ? arr.splice(index, 1);
? ? }
});

var colors = ["red", "blue", "grey"];
colors = colors.filter(function(item) {
? ? return item != "red"
});
console.log(colors); ? ?//["blue", "grey"]

Array.prototype.remove = function(dx) {
? ? if(isNaN(dx) || dx > this.length){
? ? ? ? return false;
? ? }
? ? for(var i = 0,n = 0;i < this.length; i++) {
? ? ? ? if(this[i] != this[dx]) {
? ? ? ? ? ? this[n++] = this[i];
? ? ? ? }
? ? }
? ? this.length -= 1;
};
var colors = ["red", "blue", "grey"];
colors.remove(1);
console.log(colors); ? ?//["red", "grey"]