判断元素是否为HTMLElement元素【转载】

地址：http://www.cnblogs.com/snandy/archive/2011/03/12/1981516.html

我们经常使用nodeType==1判断元素是否是一个HMTLElement元素。页面上的元素都是节点(Node)，有元素节点(Element Node)、属性节点(Attribute Node)、文本节点(Text Node)等。w3c nodeType 的定义如下

const unsigned short ELEMENT_NODE = 1;
const unsigned short ATTRIBUTE_NODE = 2;
const unsigned short TEXT_NODE = 3;
const unsigned short CDATA_SECTION_NODE = 4;
const unsigned short ENTITY_REFERENCE_NODE = 5;
const unsigned short ENTITY_NODE = 6;
const unsigned short PROCESSING_INSTRUCTION_NODE = 7;
const unsigned short COMMENT_NODE = 8;
const unsigned short DOCUMENT_NODE = 9;
const unsigned short DOCUMENT_TYPE_NODE = 10;
const unsigned short DOCUMENT_FRAGMENT_NODE = 11;
const unsigned short NOTATION_NODE = 12;

但如果我们自定义的对象也包含nodeType属性呢？如

 
       1 
        var obj = {nodeType:1};   
      
       2 
        function isHTMLElement(obj){   
      
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            if(obj.nodeType){   
      
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                return obj.nodeType==1;   
      
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            }   
      
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       }  
      
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        isHTMLElement(obj);//true

以上isHTMLElement(obj)返回true，但obj明显不是一个HTML节点元素。下面通过对象特性及try-catch语句来判断。

 
       01 
        function isHTMLElement(obj){   
      
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            var d = document.createElement("div");   
      
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            try{   
      
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                d.appendChild(obj.cloneNode(true));   
      
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                return obj.nodeType==1?true:false;   
      
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            }catch(e){   
      
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                return false;   
      
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            }   
      
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       }  
      
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        var obj1 = {nodeType:1};   
      
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        var obj2 = document.createTextNode("hello");   
      
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        var obj2 = document.createElement("p");   
      
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        isHTMLElement(obj1);//false   
      
       14 
        isHTMLElement(obj2);//false   
      
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        isHTMLElement(obj3);//true

对于window和document还要特别处理下

 
       01 
        function isHtmlControl(obj) {    
      
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            var d = document.createElement("div");   
      
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            try{   
      
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                d.appendChild(obj.cloneNode(true));   
      
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                return obj.nodeType==1 ? true : false;   
      
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            }catch(e){   
      
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                return obj==window || obj==document;   
      
       09 
            }   
      
       10 
       }

判断元素是否为HTMLElement元素【转载】

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