A '$' in a variable means nothing special to the interpreter, much like an underscore. From what I've seen, many people using jQuery (which is what your example code looks like to me) tend to prefix variables that contain a jQuery object with a $ so that they are easily identified and not mixed up with, say, integers. The dollar sign function $() in jQuery is a library function that is ...
The $ is an alias for jQuery which (jQuery) is a Javascript library. Plug-ins are usage of the library in a specific fashion which create specific use of the library and extend its functionality.
here is a code that is working: the jQuery will treat only the buttons that are of class .cls-hlpb, it will take the id of the button that was clicked and will change it according to the data that comes from the ajax.
$("div.id_100 > select > option[value=" + value + "]").prop("selected",true); Where value is the value you wish to select by. If you need to removed any prior selected values, as would be the case if this is used multiple times you'd need to change it slightly so as to first remove the selected attribute
Advantages: Straight-forward, no dependency on jQuery, easy to understand, no issues with preserving the meaning of this within the body of the loop, no unnecessary overhead of function calls (e.g., in theory faster, though in fact you'd have to have so many elements that the odds are you'd have other problems; details).
When you pass this to the jQuery constructor, you are passing the current element for a jQuery object to be constructed with. The jQuery object then contains an array-like structure of the DOM elements matching the selector (or just the single element in the case of this). Once the jQuery object is constructed, the jQuery API is now exposed.
Also, if you work with data attributes a lot in your jQuery scripts, you might want to consider using the HTML5 custom data attributes plugin. This allows you to write even more readable code by using .dataAttr('foo'), and results in a smaller file size after minification (compared to using .attr('data-foo')).
Jquery.ajax does not encode POST data for you automatically the way that it does for GET data. Jquery expects your data to be pre-formated to append to the request body to be sent directly across the wire.
jquery (E) solution is quite-fast on big tables jquery (E) and querySelectorAll (H) solutions are slowest for small tables getElementByName (G) and querySelectorAll (H) solutions are quite slow for big tables Details I perform two tests for read elements by name (A, B, C, D) and hide that elements (E,F,G,H,I) small table - 3 rows - you can run ...
