Question

After clicking on input field the datepicker does not popup.

$(document).ready(function() {
         var sds = document.getElementsByClassName("f_sd");
         for(var i = 0; i < sds.length; i ++){
                sds[i].id = i+":sd";
                 var id = "#"+i+":sd";
                 $(id).datepicker();
         }
});

Answer 1

Problem is here

sds[i].id = i+":sd"; 

control id should not contain :

JSFiddle without : in control id http://jsfiddle.net/QsgNF/1/

JSFiddle with : in control id http://jsfiddle.net/QsgNF/2/

You can see that the first fiddle without : is giving desired output where as the second fiddle is failing.