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.
It is shorthand for jQuery (). Which you can use if you want. jQuery can be ran in compatibility mode if another library is using the $ already. Just use jQuery.noConflict (). $ is pretty commonly used as a selector function in JS. In jQuery the $ function does much more than select things though.
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.
When inside a jQuery method’s anonymous callback function, this is a reference to the current DOM element. $ (this) turns this into a jQuery object and exposes jQuery’s methods. A jQuery object is nothing more than a beefed-up array of DOM elements.
$("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
You can't render a partial view using only jQuery. You can, however, call a method (action) that will render the partial view for you and add it to the page using jQuery/AJAX. In the below, we have a button click handler that loads the url for the action from a data attribute on the button and fires off a GET request to replace the DIV contained in the partial view with the updated contents.
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.
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).
