1 function test(){
 2     var x = "img/2.jpg";
 3     var arr = x.split("");
 4     for(var i=0;i<arr.length;i++){
 5         if(arr[i]=="/"){
 6             arr[i-1] += "\\";
 7         }
 8     }
 9     console.log(arr.join(""));
10 }