## 1.根据对象的属性值排序
function createComparisonFunction(propertyName){
 return function(object1,object2){
 var value1 = object1[propertyName];
 var value2 = object2[propertyName];
 if(value1 < value2){
 return -1;
 }else if(value1 > value2){
 return 1;
 }else{
 return 0;
 }
 };
}