jQuery Grid Plugin - jqGrid

I made the button that after few cells are edited saves results to DB. Communication between JS and PHP works but i cannot find easy way to transform array into JSON:

Button looks like this:

.navButtonAdd(”#pager2 ,#pager”,{caption:”Save”,title:”Save”,buttonimg: path + '/basic/images/find.gif',
    onClickButton:function(){
        if (confirm ('Sure?')) {
           changed_cells = $('#grid_table').getChangedCells('dirty');
           for(i=0;i<(changed_cells.length);i++)
          {
               rowid = changed_cells[i]['id'];
               changed_cells[i]['id_produkt']= $('#grid_table').getCell(rowid,0);
          }
          $.ajax({
             url: “translate_edit.php”,
             type: “post”,
             data: some_JSON_encode_funct(changed_cells),  
             success: function(data) {  
                 alert('Success');},
             complete: function () {
                alert('Complete');
          },
          error: function (xhr, ajaxOptions, thrownError){
             alert(xhr.valueOf());
          }
      });
    }
 }
});

1.Is there a function that transforms array into JSON(like json_encode in PHP) in jqgrid or jquery(some_JSON_encode_funct)?

2. How to erase red marker(triangle) in edited cell?

3. Is there a function that refresh content of whole page like refresh button that i could use it in a JS code?

Greetings

Majkel