Created
August 2, 2014 02:24
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简单的闭包示例
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| <!doctype html> | |
| <html lang="en"> | |
| <head> | |
| <meta charset="UTF-8"> | |
| <title>闭包示例</title> | |
| <script> | |
| /* | |
| 自己的惯性思维写的 | |
| 比较糟糕的一种方式,在循环中创建了函数，带来无谓的计算，引起混淆， | |
| 正如书本上改良后的例子，在循环外建立一个辅助函数，让这个辅助函数再返回一个绑定了当前i值的函数，这样就不会导致混淆了 | |
| */ | |
| window.onload = function() | |
| { | |
| var linkHolder = document.getElementById('links'); | |
| var linkItems = linkHolder.getElementsByTagName('a'); | |
| console.log(ul +','+ linkItems) | |
| for(var i=0;i<linkItems.length;i+=1) | |
| { | |
| linkItems[i].onclick = function() | |
| { | |
| console.log(this.innerText); | |
| return false; | |
| }; | |
| } | |
| } | |
| //书本上改良后的例子 | |
| var add_the_handlers = function(nodes) | |
| { | |
| var helper = function(i) | |
| { | |
| return function(e) | |
| { | |
| alert(i); | |
| }; | |
| }; | |
| var i; | |
| for(i=0;i<nodes.length;i+=1) | |
| { | |
| nodes[i].onclick = helper(i); | |
| } | |
| } | |
| </script> | |
| </head> | |
| <body> | |
| <ul id="links"> | |
| <li><a href="#">01</a></li> | |
| <li><a href="#">02</a></li> | |
| <li><a href="#">03</a></li> | |
| <li><a href="#">04</a></li> | |
| <li><a href="#">05</a></li> | |
| </ul> | |
| </body> | |
| </html> |
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