image_html/css_WEB-ITnose-HTML Tutorial-php.cn

image_html/css_WEB-ITnose

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Release： 2016-06-24 11:34:49

Original

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回复讨论(解决方案)

document.getElementById("aa").innerHTML = parseInt(document.getElementById("aa").innerHTML, 10) + i

用闭包

(function (i) {	img.onload = function () {		..............	}})(i);

Copy after login

<!DOCTYPE html><html lang="en"><head>    <meta charset="UTF-8">    <title>Document</title></head><body><button>button1</button> <br><button>button2</button> <br><button>button3</button> <br><button>button4</button> <br><hr><a>anchor1</a> <br><br><a>anchor2</a> <br><br><a>anchor3</a> <br><br><a>anchor4</a> <br><br><script>        var btns = document.getElementsByTagName("button");    for ( var i = 0; i < btns.length; i++ ) {        btns[i].onclick = function handler() {            //alert( this.innerHTML )            console.info( i, this.innerHTML );             /* 输出                4 "button1"                4 "button2"                4 "button3"                4 "button4"            */        }    }    alert( i ); //=> 4，JS中没有局部变量(不考虑ES6)    /*        这是因为，局部变量i在函数handler调用时，依然有效；        函数handler的调用，发生在整个for循环执行完毕后，此时i=4    */    </script>   <script>    var anchors = document.getElementsByTagName("a");    for ( var i = 0; i < btns.length; i++ ) {        ( function ( x ) {            anchors[x].onclick = function() {                console.info( x, this.innerHTML );             };        } ) ( i );    }    /*        将变量i的值传递到立即执行的函数 (function(x){})(i),        这样，每次循环， x 的值就为当次循环的i的值，而不是直接引用变量i    */</script></body></html>

Copy after login

采用闭包成功解决了问题，谢谢各位同仁大神的帮助