A robust isNativeObject()

isNativeObject.js

var isNativeObject = (function( window ){

	var a = "Boolean Number String Function Array Date RegExp Object".split(" "),
		natives = {},

		hostTypes = {
			"object": 1,
			"function": 1
		},

		toStr = natives.toString,
		slice = a.slice,

		sliceTest = function( obj ) {
			try {
				slice.call( obj );
				return 0;
			} catch (e) {
				return 1;
			}
		};

	while ( a[0] ) {
		natives[ "[object " + a.pop() + "]" ] = 1;
	};

	if ( sliceTest(window) ) {
		sliceTest = 0;
	}

	return function( obj ) {
		return obj != null && toStr.call( obj ) in natives &&
			// Additional checks for IE6, IE7, IE8.
			( !sliceTest || !hostTypes[ typeof obj ] || "hasOwnProperty" in obj && !( "length" in obj && sliceTest( obj ) ) );
	};

})( this );

isNativeObject.min.js

var isNativeObject=function(e){for(var c="Boolean Number String Function Array Date RegExp Object".split(" "),d={},f={object:1,"function":1},g=d.toString,h=c.slice,b=function(a){try{return h.call(a),0}catch(b){return 1}};c[0];)d["[object "+c.pop()+"]"]=1;b(e)&&(b=0);return function(a){return a!=null&&g.call(a)in d&&(!b||!f[typeof a]||"hasOwnProperty"in a&&!("length"in a&&b(a)))}}(this);

Tests.

Not supporting:

• Host methods.
• Special objects like window.location.
• Math object.
• Error instances.