js中的call

//例1

    <script>

        window.color = 'red';

        document.color = 'yellow';

        var s1 = {color: 'blue' };

        function changeColor(){

            console.log(this.color);

        }

        changeColor.call();         //red (默认传递参数)

        changeColor.call(window);   //red

        changeColor.call(document); //yellow

        changeColor.call(this);     //red

        changeColor.call(s1);       //blue

    </script>

    //例2

    var Pet = {

        words : '...',

        speak : function (say) {

            console.log(say + ''+ this.words)

        }

    }

    Pet.speak('Speak'); // 结果：Speak...

    var Dog = {

        words:'Wang'

    }

    //将this的指向改变成了Dog

    Pet.speak.call(Dog, 'Speak'); //结果： SpeakWang
巴特西

js中的call

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