Javascript数组(array) sort方法的解释和分析

var arrA = [6,2,4,3,5,1]; 
 /**//*arrA.sort(); 
 document.writeln(arrA); 
 */ 
 function desc(x,y) 
 ...{ 
     if (x > y)   
         return -1; 
     if (x < y)           
         return 1; 
 } 
 function asc(x,y) 
 ...{ 
     if (x > y)   
         return 1; 
     if (x < y)           
         return -1; 
 } 
 arrA.sort(desc);    // sort by desc 
 document.writeln(arrA); 
 document.writeln("<br>"); 
 arrA.sort(asc);    //sort by asc 
 document.writeln(arrA);