$('#MyButton').on("click",function(){ $("#selecttest").attr("size", 8); $("#selecttest").css("position","fixed"); $('#MyButton').css("margin-left", $("#selecttest").width() + 5);}); $('#selecttest').on("change",function(){ $("#selecttest").attr("size", 1);});
var myDropDown=$("#myDropDown"); var length = $('#myDropDown> option').length; //open dropdown myDropDown.attr('size',length);