The first way to fail

  Among them c1 c2  Is the name of a global variable 
  With c1 c2  Different , change   Global variable with corresponding name   The content of 
  My code below is wrong , It is impossible to change the contents of global variables , I don't know how to change it 
 <script type="text/javascript">
    var c1 =  [{
     id: 1, text: ' guangdong ' }];
	var c2 =  [{
     id: 1, text: ' guangdong ' }];
    function change(){
    
        listDict("cost","0",c1);// change c1 Global variable of // Call area 
        listDict("codddst","0",c2);
}
    change();// Set to open the page and start immediately 

    // Method area 
    function listDict(dtype,dPid,c){
    
        ……………………………………
        Layers.AjaxProxy({
    
            …………
            data: data ,
            dataType: 'json',,
        }).done(function (result, flag) {
              
             if (flag) {
    //
               ……………………………………………………
               c=…………;// This will not change 
            }//
            }); 
          }

</script>

Later solutions

The solution is to use return Methods
Change the global variable to c1 = Method ; Add return

var c1 =  [{
     id: 1, text: ' guangdong '}];
var c2 =  [{
     id: 1, text: ' background ', pid: 1 }];
function changeSelect(){
    
        //-----------------------------
        c1 = listDict("costType","0",c1);// A key part 
        c2 = listDict("costType","",c2);//
    }
    changeSelect();// Set to open the page and start immediately 


function listDict(dtype,dPid,c){
    
        ……………………………………
        Layers.AjaxProxy({
    
            cache: false ,
            type: "get" ,
            url: "${request.contextPath}/d4d4/dddd" ,
            data: data ,
            dataType: 'json',
            async: false    ,
        }).done(function (result, flag) {
    
            if (flag) {
    //
                ……………………………………………………
            }//
        });
        return c;// A key part 
    }