jQuery.isFunction源码

Question

var isFunction = function isFunction( obj ) {

      // Support: Chrome <=57, Firefox <=52
      // In some browsers, typeof returns "function" for HTML <object> elements
      // (i.e., `typeof document.createElement( "object" ) === "function"`).
      // We don't want to classify *any* DOM node as a function.
      return typeof obj === "function" && typeof obj.nodeType !== "number";
  };

为什么要写这句typeof obj.nodeType !== "number";
是兼容ie吗

Answer 1

有些浏览器把dom节点的类型是function，因此我们要排除这种情况。凡是nodeType是数字类型都是节点。因此nodeType不是数值类型即排除dom节点

Answer 2

      // In some browsers, typeof returns "function" for HTML <object> elements
      // (i.e., `typeof document.createElement( "object" ) === "function"`).
      // We don't want to classify *any* DOM node as a function.

DOM Node 有一个数值型 nodeType 属性。