js判断对象是否相等

function equals( x, y ) { 
	var in1 = x instanceof Object;
	var in2 = y instanceof Object;
	if(!in1||!in2){
	  return x===y;
	}
	if(Object.keys(x).length!==Object.keys(y).length){
	  return false;
	 }
	for(var p in x){
	var a = x[p] instanceof Object;
	var b = y[p] instanceof Object;
	  if(a&&b){
	    return equals( x[p], y[p]);
	   }
	   else if(x[p]!==y[p]){
	     return false;
	   }
	}
	
	return true;
} 
 
alert(equals({a:1},{a:1}));//true