对于javascript原型的一些检验01

末蓝、 2022-06-01 04:24 131阅读 0赞

**今天，恰好有时间，就对自己一直不是很清楚的js原型进行了一些思考和验证，所用软件为Hbuilder，不多说了，直接上代码和结果：**

<!DOCTYPE html>
 <html>
 	<head>
 		<meta charset="UTF-8">
 		<title></title>
 	</head>
 	<body>
 		
 			在JavaScript里，任何函数都可以添加到对象上作为
 			对象的属性。函数的继承与其他属性继承没有差别，
 			包括上面的“属性覆盖”（这种情况相当于其他语言的方法
 			重写）
 		
 		
 			只有函数才有prototype属性
 		
 		
 		<script type="text/javascript">
 			var o = {
 				a:1,
 				b:2
 			};
 			//undefinded
 			//只有函数才有prototype属性
 			document.write(o.prototype+" ");
 			//undefined
 			window.document.write(Object.prototype.prototype+" ");
 			//[object Object]
 			window.document.write(Object.prototype+" ");
 			//function Empty() {}
 			window.document.write(Object.__proto__+" ");
 			//function Empty() {}
 			window.document.write(Function.prototype+" ");
 			//function Empty() {}
 			window.document.write(Function.__proto__+" ");
 			//false !!!
 			document.write((Object.__proto__ === Object.prototype)+" ");
 			//true
 			document.write((Function.prototype === Function.__proto__)+" ");
 			//true
 			document.write(o.__proto__ === Object.prototype);
 			document.write(" ");
 			//null
 			document.write(o.__proto__.__proto__+" ");
 			
 			//对o.__proto__重新赋值
 			o.__proto__ = {
 				c:3,
 				d:4
 			};
 			//
 			o.prototype = {e:5};
 			//[object Object]
 			document.write(o.prototype+" ");
 			//[object Object]
 			document.write(o.__proto__+" ");
 			//3
 			document.write(o.__proto__.c+" ");
 			//4
 			document.write(o.__proto__.d+" ");
 			//[object Object]
 			document.write(o.prototype+" ");
 			//5
 			document.write(o.prototype.e+" ");
 			//undefined
 			document.write(o.prototype.c+" ");
 			//[object Object]
 			document.write(o.__proto__.__proto__+" ");
 			//null
 			document.write(o.__proto__.__proto__.__proto__+" ");
 			//false
 			document.write(o.__proto__ === Object.prototype+" ");
 			document.write(" ");
 			document.write('------------------------------'+' ');
 			
 			var foo = function(){
 				return 111;
 			}
 			//[object Object]
 			document.write(foo.prototype+" ");
 			//function Empty() {}
 			document.write(Function.prototype+" ");
 			//function Empty() {}
 			document.write(foo.__proto__+" ");
 			//false
 document.write((foo.prototype === Function.prototype)+" ");
 			//true
 			document.write((foo.__proto__ === Function.prototype)+" ");
 			//true
 			document.write((Function instanceof Object)+" ");
 			//true
 			document.write((Object instanceof Function)+" ");
 			//function Function() { [native code] }
 			document.write(foo.constructor+" ");
 			//function (){ return 111; }
 			document.write(foo.prototype.constructor+" ");
 		</script>
 	</body>
 </html>