function testDwrParam(){
                    var a=document.getElementById("a").value;
                    var b=document.getElementById("b").value;
                    var c=document.getElementById("c").value;
                    var sumG=0;
                    testDwrJs.invokeByDwrParam(a,b,c,function(sum){
                            sumG=sum;
                            alert(sum);
                    });
                    alert(sumG);
            }