I want to change the width and height of a div. data attributes did not change it. Instead I use:
var size = $("#theme_photo_size").val().split("x");
$("#imageupload_img").width(size[0]);
$("#imageupload_img").attr("data-width", size[0]);
$("#imageupload_img").height(size[1]);
$("#imageupload_img").attr("data-height", size[1]);
be careful:
$("#imageupload_img").data("height", size[1]); //did not work
did not set it
$("#imageupload_img").attr("data-height", size[1]); // yes it worked!
this has set it.