JQuery :: Add Control Id Dynamically?

$("div").prepend("<button id ='b10'>X</button>");

Above code is working but i want to enter a user wanted value for id which i am getting dynamically thru ajax request it is not working

$("div").prepend("<button>X </button>").setAttribute("id","b"+number);

My Full code is::-
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$(document).ready(function() {
//First Method
$("button").click(function() {
var bid= $(this).attr('id');

[Code]...