ExtJS Element.js
Eclement.js里的一段代码:
Ext.Element = function(element, forceNew){
var dom = typeof element == "string" ?
DOC.getElementById(element) : element,
id;
if(!dom) return null;
id = dom.id;
if(!forceNew && id && Ext.elCache[id]){ // element object already exists
return Ext.elCache[id].el;
}
/**
* The DOM element
* @type HTMLElement
*/
this.dom = dom;
/**
* The DOM element ID
* @type String
*/
this.id = id || Ext.id(dom);
};
请问:
var dom = typeof element == "string" ?
DOC.getElementById(element) : element,
id;
怎么解?