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IOS 5 (safari) bug with HTML touch events on "position:fixed" div

I have a position:fixed div on a scrolling web page.

At first the event works, but when the page scroll, while the fixeed divs stays in place, its "touch" zone seems to change (it seems to scroll - except on top of another div, or depending on the page layout...). Eventually no touch event is received any more if you scroll too much. Sometimes the underlying div receives the event instead.

Here's the sample:

<html>
  <head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    <meta name="viewport" content="width=device-width; initial-scale=1.0; maximum-scale=1.0; user-scalable=no;">
    <meta name="apple-mobile-web-app-capable" content="yes" />

<style>
#fixed {
  position: fixed;
  width:200px;
  height:200px;
  z-index:1;
  background: rgba(100,0,0,0.5);
}

#scrolling {
  display: block;
  position: absolute;
  top: 100px;
  left: 100px;
  width:200px;
  height:999px;
  background: rgba(0,100,0,1);
}
</style>
</head>

<body>
  <div id="fixed"     ontouchend="alert('touch fixed')"></div>
  <div id="scrolling" ontouchend="alert('touch scrolling')"></div>
</body>

When you scroll enough and touch the red "fixed" div on its left side, nothing happens (no alert). However, on the right side (above the green scrolling div) it works... ?!

Looks like a Safari bug to me. Do you experience the same? Any idea for a workaround? (Iscroll is out of question - too slow)

Thank you, LC

like image 396
lacorbeille Avatar asked Jan 10 '12 19:01

lacorbeille


5 Answers

I found a relatively strange solution to this bug. By adding a touchstart event listener and a blank event handler, it somehow seems to move the touch area on manual touch. I do not know if this is a solution for the JavaScript scroll issue.

Code:

document.getElementsByTagName("body")[0].addEventListener("touchstart",function(){});

Credit for finding this method goes to pamelafox in this github bug discussion.

like image 81
Gaurav Shetty Avatar answered Nov 15 '22 14:11

Gaurav Shetty


I'm having the same issue. It seems to be a z-index problem, when the divs are moved programmatically (with animations, etc.): the div in fixed position doesn't work properly since the user doesn't touch again for scrolling. Only in this last case the divs seems to be recomputed correctly.

like image 40
Andrea Avatar answered Nov 15 '22 14:11

Andrea


I had this problem. The way I got round it was to bind to "click" instead of "touchstart".

This meant that my "click" events got messed up (for users not on touch devices) so I detected a hover first and then used the hover to tell me if they were touch users or not. A bit dirty, but it works!

like image 39
scruffian Avatar answered Nov 15 '22 14:11

scruffian


I found this bug too, but the below seemed to clear it up for me:

<meta name="viewport" content="width=device-width, height=device-height, initial-scale=1.0, user-scalable=0, minimum-scale=1.0, maximum-scale=1.0">`

add it to your html header

like image 26
cjroebuck Avatar answered Nov 15 '22 12:11

cjroebuck


I ran into the same issue using a fixed position navigation that scrolls the user around the page using jQuery animation. I don't believe it's a z-index issue. What I found is that when the animation moves the viewport, the fixed position element is actually still at the previous location until the user touches and moves the screen. At that point the position of the nav is updated. More information and demo here: http://bit.ly/ios5fixedBug

like image 29
Erik Runyon Avatar answered Nov 15 '22 12:11

Erik Runyon