Touch-compatible JS quick navigation scrubber? - javascript

In long lists on iOS there exists a quick navigation "scrubber" on the right-hand side that you can brush your finger across to quickly jump from one item to the next, e.g. in the Music app if you have enough music available you'll see ABCD... allowing you to quickly jump to that letter of the alphabet in your list.
Does anyone know of a library or plugin to recreate this touch-based behavior on a website using anchor tags?
If not, are there any recommended approaches? My current thoughts are to disable touch events for the anchors if possible and capture touchbegin and touchmove on the parent div, then compare the coordinates of the touch with the coordinates of the anchor tags and fire off artificial 'click' events to cause the navigation.
Thanks in advance for any help.

https://github.com/desmosinc/scrubber
Simple, attractive html+js scrubber control.
Tested in recent versions of Firefox, Chrome, Safari, and IE9+. Works
with mouse events and touch events.

Related

Hybrid PC/Tablet website

What is the reliable approach to develop a website that is used on the computer that is a hybrid, in other words have both a mouse (or a touch pad) and a touch screen and can be used by a user in both ways at the same time.
Especially the question is how to deal with the mouse cursor, that must be seen when using a mouse and is distracting once the user uses her finger.
The goal is to develop a single page, not two separate pages, one for mouse and other for the touch. Style cursor = 'none' is killing the cursor over the specified elements completely, this is not desired.
I am not talking about scrolling or zooming, but about clickable/touchable divs/spans/images, that can react some how. For instance I have a table where each cell could be clicked to mark (change color). Same with buttons, once you touch the button with the finger, the mouse cursor will stay on top of it and distract.
HTML5 does support the concept of touch events, perhaps you can dynamically change behavior/style etc in javascript based on detected events (e.g. turn your page into touch mode "cursor = none" if you detect a touch event but switch back to mouse visible style if you detect mouse move events).
This is by no means completely reliable as touchevent implementation is browser (somewhat patchy support at that), OS and possibly hardware dependent. e.g. Older OSes might translate touch event into mouse click events or older browsers might not support OS's touch events and OS fallsback to mouse click events.
See Touch And Mouse for more info that might help you.

Is it possible to know if a real mouse is used on a device with touch features using javascript?

I'am working on a web site and I'am using modernizer to know if a device is touch compatible.
In this case, i filter all 'hover' of html tags of my application.
example : .no-touch div.cell:hover
But how can I know if the user also uses a real mouse on a touch device ?
More and more devices allow both and i want to display 'hover' on touch devices when a user prefers to use a mouse instead of (touch).
I'am using angularjs then a related solution should be great.
Thanks
Mouse events should trigger click events, whereas Touch events should trigger the touch events. However, let it be known now that some touch screens (typically older models) don't have "real" touch capability. All they do is take the touch input and convert it into clicks.
Also, I don't think the :hover attribute ever cares if it's mouse or touch. I think the only calculation that goes into that is whether or not the cursor is above the given element.

How to detect when multitouch finger moves onto child element?

My implementation works great with a mouse where I can use a delegated jQuery on("mousemove","*") handler to detect when the user mouses over something and this triggers an action.
I want to do the same for multi-touch, if the user drags their finger across a child element I want a delegated touchmove handler to pick it up. However it seems like only the callback of the container element ever gets called as the finger is dragged around on that container (and over its child elements).
Is there some way I can accomplish this without writing a point-in-rect test using JS?
Fiddle here.
Notice how on a PC when you click-drag across the B DIV it gets turned red correctly.
On an iOS device (with debug console enabled) you can only get it to show up blue (by tapping inside the 'B' div). I want to be able to drag over something and "pick it up".
Behavior is also identical on a Nexus 7 Android 4.1.1 tablet with (Mobile) Chrome.
It would appear that a previous discussion provides an unsatisfactory but workable solution to my problem:

Scroll event on Android Browser not firing. Need workaround

I've created a website with a parallax street scene. See here for an archived version.
It works just fine on all major desktop browsers, and Safari Mobile. It works fine in Mobile Firefox and Chrome for Android Beta also. However the default Android browser has issues with the scroll event. Let me be clear. Scrolling is not the issue. The div scrolls as required. The scroll event doesn't fire. This issue I experience on Honeycomb as well as ICS.
I'm not concerned about other mobile browsers because for mobile screen sizes one usually does not see the parallax scene; mediaqueries and conditional JavaScript loading take care of that. Responsive design and all that jazz.
Basically, I've written a parallise() jQuery plugin that positions each image based on its position and 'depth'. This function is bound to the scroll event.
On Android Browser, this event only fires at the start of the next touch, instead of continuously.
OK, so I thought that perhaps if I bound the function to touchstart, touchmove, and touchend events I would solve my issue. No cigar. Other touch events are also bugged. Applying the suggested workaround causes the events to fire, but as I have to e.preventDefault(), scrolling (the whole point of the exercise) is disabled.
What if I just poll the position of the stage div relative to the window div? Turns out that the position information is only updated at the start of the next touch.
I am at the end of my tether. Any help would be much appreciated.
Even if the touch events worked correctly on the bugged versions of Android, and you were then effectively able to track the native scroll position during a drag, this would be prone to error. For example, it wouldn't account for the momentum animation which happens after the touching has finished.
iOS and Android make sacrifices to improve the performance of scrolling. On both platforms, it's not possible to get the accurate scroll position until the scroll has completed. The scroll event (on the <body>) doesn't fire until the momentum animation is finished. So while your original question is about scroll events on an overflowing <div>, fixing this might not be totally helpful for you anyway.
If you want an animation to update in time with the scroll, then you need to perform the scroll programatically rather than using the browser's native scroll. The best library to do this is iScroll. You can achieve parallax effects very easily as seen in this demo.
If you need more complex effects (the walking character, in your example), you can opt for the "probe" version of iScroll which allows pixel-perfect polling of scroll position in return for reduced performance.
However, there are many downsides to using iScroll:
You may need to change your markup and styling
It is unnecessary overhead for desktop browsers, but due to markup changes may be difficult to use only as a fallback
The scrolling will not feel perfect - on iOS, with its usually excellent scrolling performance - the slight difference in momentum calculation can feel jarring. On Android, the scrolling can become more laggy than usual.
Swipe shim that doesn't need preventdefault on touchstart: https://github.com/TNT-RoX/android-swipe-shim

Web iPad app - how to differentiante between one- and two- finger scrolls

Doing Web app for iPad clients, but need to recognize where user is doing one- and whe two-finger scrolls. Anybody know how to implement it? Any convenient jQuery plug in or something? Thanks.
I'm going to assume that by 'scroll' you mean the panning gesture.
Looking at Handling Events documentation for mobile Safari it would seem that unless the element is scrollable you wont be able to detect any difference using the high-level DOM-events (both the one- and two-finger
panning gesture will result in an onscroll event when movement stops).
If, the element is scrollable you'll receive a series of mousewheel events instead.
If you'd be willing to get your hands a little dirty you should have a look at the section called 'Handling Multi-Touch Events'. You could probably achieve what you want by opting-in to receive the more low-level multi-touch events (touchStart, touchMove, touchEnd, touchCancel). The event object passed to the handlers of these events contains a 'touches' property which allows you to look at the position of all "fingertips". That'd propably give you all information you need.
Don't forget to prevent the default behavior though, otherwise you'll still receive the onscroll and/or mousewheel events.
Have a look at the "virtual light table" demo for some inspiration on handling multi touch events in javascript. There's also an excellent article at sitepen.com that you should have a look at.

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