Drag and Drop using jquery

jquery code in drag and drop textfield

<a href="#" id="menu" onchange="add_textbox_drop" > Textbox </a>

$(function () {

$("#menu").draggable({
revert: "valid"
});


$('#menu').droppable({
drop: function (event, ui) {
var parenttd = $(this).attr('id');
//alert("parenttd=" + parenttd);
$(this).append('');
}
});
});