Module Js_of_ocaml_lwt.Lwt_js_events

make_event ev target creates a Lwt thread that waits for the event ev to happen on target (once). This thread isa cancellable using Lwt.cancel. If you set the optional parameter ~use_capture:true, the event will be caught during the capture phase, otherwise it is caught during the bubbling phase (default). If you set the optional parameter ~passive:true, the user agent will ignore preventDefault calls inside the event callback.

seq_loop (make_event ev) target handler creates a looping Lwt thread that waits for the event ev to happen on target, then execute handler, and start again waiting for the event. Events happening during the execution of the handler are ignored. See async_loop and buffered_loop for alternative semantics.

For example, the clicks function below is defined by:

let clicks ?use_capture ?passive t = seq_loop click ?use_capture ?passive t

The thread returned is cancellable using Lwt.cancel. In order for the loop thread to be canceled from within the handler, the latter receives the former as its second parameter.

By default, cancelling the loop will not cancel the potential currently running handler. This behaviour can be changed by setting the cancel_handler parameter to true.

async_loop is similar to seq_loop, but each handler runs independently. No event is thus missed, but since several instances of the handler can be run concurrently, it is up to the programmer to ensure that they interact correctly.

Cancelling the loop will not cancel the potential currently running handlers.

buffered_loop is similar to seq_loop, but any event that occurs during an execution of the handler is queued instead of being ignored.

No event is thus missed, but there can be a non predictable delay between its trigger and its treatment. It is thus a good idea to use this loop with handlers whose running time is short, so the memorized event still makes sense when the handler is eventually executed. It is also up to the programmer to ensure that event handlers terminate so the queue will eventually be emptied.

By default, cancelling the loop will not cancel the (potential) currently running handler, but any other queued event will be dropped. This behaviour can be customized using the two optional parameters cancel_handler and cancel_queue.

async t records a thread to be executed later. It is implemented by calling yield, then Lwt.async. This is useful if you want to create a new event listener when you are inside an event handler. This avoids the current event to be caught by the new event handler (if it propagates).

func_limited_loop event delay_fun target handler will behave like Lwt_js_events.async_loop event target handler but it will run delay_fun first, and execute handler only when delay_fun is finished and no other event occurred in the meantime.

This allows to limit the number of events caught.

Be careful, it is an asynchrone loop, so if you give too little time, several instances of your handler could be run in same time *

Same as func_limited_loop but take time instead of function By default elapsed_time = 0.1s = 100ms *

This function returns the event, together with the numbers of ticks the mouse wheel moved. Positive means down or right. This interface is compatible with all (recent) browsers.

Returns when a CSS transition terminates on the element.

Returns when a repaint of the window by the browser starts. (see JS method window.requestAnimationFrame)

Returns when the page is loaded