98 lines
1.9 KiB
Markdown
98 lines
1.9 KiB
Markdown
1.
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window.color = 'red';
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document.color = 'yellow';
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var s1 = {color: 'blue' };
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function changeColor(){
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console.log(this.color);
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}
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changeColor.call(); //red (默认传递参数)
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changeColor.call(window); //red
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changeColor.call(document); //yellow
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changeColor.call(this); //red
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changeColor.call(s1); //blue
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2
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var Pet = {
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words : '...',
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speak : function (say) {
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console.log(say + ''+ this.words)
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}
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}
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Pet.speak('Speak'); // 结果：Speak...
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var Dog = {
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words:'Wang'
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}
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//将this的指向改变成了Dog
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Pet.speak.call(Dog, 'Speak'); //结果： SpeakWang
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3
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用 apply重写上面两个函数
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4
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function add(c,d){
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return this.a + this.b + c + d;
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}
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var s = {a:1, b:2};
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console.log(add.call(s,3,4)); // 1+2+3+4 = 10
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console.log(add.apply(s,[5,6])); // 1+2+5+6 = 14
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5.画出原型链
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//游戏--->王者---->小乔---->花嫁
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6
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function C1(name) {
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if (name) {
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this.name = name;
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}
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}
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function C2(name) {
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this.name = name;
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}
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function C3(name) {
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this.name = name || 'join';
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}
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C1.prototype.name = 'Tom';
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C2.prototype.name = 'Tom';
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C3.prototype.name = 'Tom';
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alert((new C1().name) + (new C2().name) + (new C3().name));
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7
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function Fn(num) {
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this.x = this.y = num;
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}
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Fn.prototype = {
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x: 20,
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sum: function () {
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console.log(this.x + this.y);
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}
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};
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let f = new Fn(10);
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console.log(f.sum === Fn.prototype.sum);
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f.sum();
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Fn.prototype.sum();
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console.log(f.constructor);
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8
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var print=function(){alert(1);}
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function Fn() {
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print=function(){alert(2);}
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return this;
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}
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function print(){alert(3);}
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Fn.prototype.print=function(){alert(4);}
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Fn.print=function(){alert(5);}
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print();
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Fn.print();
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Fn().print();
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new Fn.print();
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new Fn().print();
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