JavaScript for循环与闭包：解决点击事件输出错误的7种方案

<html >   
<head>   
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />   
<title>闭包演示</title>   
<script type="text/javascript">   
  
function init() {   
  var pAry = document.getElementsByTagName("p");   
  for( var i=0; i<pAry.length; i++ ) {   
     pAry[i].onclick = function() {   
     alert(i);   
  }   
 }   
}   
</script>   
</head>   
<body onload="init();">   
<p>产品一</p>   
<p>产品二</p>   
<p>产品三</p>   
<p>产品四</p>   
<p>产品五</p>   
</body>   
</html>  

function init() {   
 var pAry = document.getElementsByTagName("p");   
 for( var i=0; i<pAry.length; i++ ) {   
   pAry[i].i = i;   
   pAry[i].onclick = function() {   
    alert(this.i);   
   }   
 }   
}   

function init2() {   
 var pAry = document.getElementsByTagName("p");   
 for( var i=0; i<pAry.length; i++ ) {    
  (pAry[i].onclick = function() {   
    alert(arguments.callee.i);   
  }).i = i;   
 }   
} 

function init3() {   
 var pAry = document.getElementsByTagName("p");   
 for( var i=0; i<pAry.length; i++ ) {   
  (function(arg){     
    pAry[i].onclick = function() {     
     alert(arg);   
    };   
  })(i);//调用时参数   
 }   
}   

function init4() {   
 var pAry = document.getElementsByTagName("p");   
 for( var i=0; i<pAry.length; i++ ) {    
  (function () {   
   var temp = i;//调用时局部变量   
   pAry[i].onclick = function() {    
    alert(temp);    
   }   
  })();   
 }   
}   

function init5() {   
 var pAry = document.getElementsByTagName("p");   
 for( var i=0; i<pAry.length; i++ ) {    
  pAry[i].onclick = function(arg) {   
    return function() {//返回一个函数   
    alert(arg);   
   }   
  }(i);   
 }   
}  

function init6() {   
  var pAry = document.getElementsByTagName("p");   
  for( var i=0; i<pAry.length; i++ ) {    
   pAry[i].onclick = new Function("alert(" + i + ");");//new一次就产生一个函数实例  
  }   
}  

function init7() {   
  var pAry = document.getElementsByTagName("p");   
  for( var i=0; i<pAry.length; i++ ) {   
     pAry[i].onclick = Function('alert('+i+')')  
  }   
}