Well, I have this jQuery image slideshow that uses the attribute \"control\" inside an . Seeing how it didn\'t validate I searched for a way to add this attribute i
Use jQuery's attr function
$("#previous").attr("control", "-6");
An example
// Try to retrieve the control attribute
// returns undefined because the attribute doesn't exists
$("#previous").attr("control");
// Set the control attribute
$("#previous").attr("control", "-6");
// Retrieve the control attribute (-6)
$("#previous").attr("control");
See this example on jsFiddle
You can alternatively use data function to store values on elements. Works the same way, for example:
$("#previous").data("control"); // undefined
$("#previous").data("control", "-6"); // set the element data
$("#previous").data("control"); // retrieve -6
Using data you can store more complex values like objects
$("#previos").data("control", { value: -6 });
($("#previos").data("control")).value; // -6
See a data example on jsFiddle