javascript移动ModalDialog

var i=0;
var intervalID=0;
function intervalstart(){
??? intervalID=window.setInterval("movedlg()",300);??
}
function movedlg(){
??? i=i+1;
??? if(i>=5){
??? ??? window.clearInterval(intervalID);??
??? }
??? var top=260-i*10;
??? window.dialogTop=top;

}