jquery isType() 类型判断代码

class2type = {}; 
toString = Object.prototype.toString; 
type: function( obj ) { 
return obj == null ? 
String( obj ) : 
class2type[ toString.call(obj) ] || "object"; 
}, isFunction: function( obj ) { 
return jQuery.type(obj) === "function"; 
}, 
isArray: Array.isArray || function( obj ) { 
return jQuery.type(obj) === "array"; 
}, 
// A crude way of determining if an object is a window 
isWindow: function( obj ) { 
return obj && typeof obj === "object" && "setInterval" in obj; 
}, 
isNaN: function( obj ) { 
return obj == null || !rdigit.test( obj ) || isNaN( obj ); 
},