how to set value to a data in js code example

Example 1: jquery get data attribute value

/* html */
<a data-id="123">link</a>

/* js */
$(this).attr("data-id") // returns string "123"

$(this).data("id") // returns number 123 (jQuery >= 1.4.3 only)

Example 2: jquery set data attribute value

//<div id="myElementID" data-myvalue="37"></div>
var a = $('#myElementID').data('myvalue'); //get myvalue
$('#myElementID').data('myvalue',38); //set myvalue