To get the contents of the attribute data-id (like in link) you have to use
$(this).attr(“data-id”) // will return the string “123”
or .data() (if you use newer jQuery >= 1.4.3)
$(this).data(“id”) // will return the number 123
and the part after data- must be lowercase, e.g. data-idNum will not work, but data-idnum will.
If we want to retrieve or update these attributes using existing, native JavaScript, then we can do so using the getAttribute and setAttribute methods as shown below:
Through JavaScript
Through jQuery
// Fetching data
var fruitCount = $(this).data(‘fruit’);
OR
// If you updated the value, you will need to use below code to fetch new value
// otherwise above gives the old value which is intially set.
// And also above does not work in ***Firefox***, so use below code to fetch value
var fruitCount = $(this).attr(‘data-fruit’);
// Assigning data
$(this).attr(‘data-fruit’,’7′);
Read this documentation