1.new_file.htm
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "<html>
?<head>
??<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
??<title>Untitled Document</title>
??<SCRIPT type='text/javascript' src='new_file.js'></SCRIPT>
??<SCRIPT type='text/javascript'>
???window.onload = load;
??</SCRIPT>
?</head>
?<body>
??<CENTER><INPUT type='button' id='b1'></INPUT></CENTER>?
?</body>
</html>
2.new_file.js
var value = '500';
function load(){
?var domEl = document.getElementById('b1');?
?JsButton(value,domEl);
}
function JsButton(value,domEl){
?this.domEl = domEl;
?this.value = value;
?this.domEl.buttonObj = this;
?//this.domEl.onclick = function(){
??//alert(this.value);
?//}
?this.domEl.onclick = JsButton.prototype.clickHandler;
}?
JsButton.prototype.clickHandler = function(){
?//alert(this.value); 在回調函數中調用this屬性時﹐
?//得到的是對應的DOM元素裡面的數值﹐此處為空。
?var buttonObj = this.buttonObj;
?var value =(buttonObj && buttonObj.value)? buttonObj.value:"unknown value";
?alert(value);
}