判断元素是否为HTMLElement元素

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？如下：

 

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

 

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

 

增加个函数判断window和document的情况，函数名isHTMLControl

 

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