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