CODEWITHSUNDEEP
iosgoogle-chromememorymemory-leakscrash
davidtheclark
davidtheclark

Reputation: 4676

Why does simple website crash on mobile (iOS Safari and Chrome, at least)?

I have a website that is very simple, but very long -- a lot of text that could be scrolled through. It's a documentation site, and considering the nature of the content (a lot of short similar entries) I decided to show everything at once, so the user could either scroll from entry to entry or navigate via a sidebar index. It's a common documentation model that I like (e.g. Underscore, Backbone, and LoDash).

The site is here: http://davidtheclark.github.io/scut/. You could look at the pre-production code here: https://github.com/davidtheclark/scut/tree/master/docs/dev.

And here's the problem: For a number of users this site consistently crashes their iOS browsers. Not all users (not me); but for those that do experience the crash, it seems to recur consistently. (The site may also crash some people's Android phones, I don't know: haven't heard from any Android users.) I am hoping someone can help me diagnose and possibly fix this problem.

Part of the difficulty I have is that I cannot reproduce the crash myself -- not on my own iOS devices, not on the Xcode simulators. Because the site is not at all resource-heavy (~70KB load) and involves very little JavaScript, and because of the effects of a few prior attempts to fix this, I'm guessing that the problem involves memory usage -- that iOS browsers are crashing because the site is demanding too much memory. But I'm not sure that's the issue, and if it is I'm not sure how I can fix it.

I'm not sure what to try next, and I'm hoping some savvy StackOverflow whizzes have advice. What is it about this site, which seems so simple and basic to my eyes, that is making it so memory-demanding that it is crashing browsers?

Is it just too long? Is there CSS that is too difficult to render? Are there JavaScript memory leaks?

I'm interested both for the sake of this particular site and so that I can learn to anticipate-and-prevent and/or diagnose-and-fix similar problems on other sites in the future.

Feel free to look at or contribute to [the Github issue](in this Github issue, as well.

Addendum

Here are some things to know about the site that might be relevant:

An iOS Crash Log

These look to me to be the potentially relevant lines of a crash report from an iPhone running Chrome and crashing on the site (I'm not sure whether they are actually relevant or not because I haven't developed iOS apps and don't know the ins-and-outs of these reports):

Free pages:                              5674
Active pages:                            117674
Inactive pages:                          55121
Speculative pages:                       3429
Throttled pages:                         0
Purgeable pages:                         0
Wired pages:                             60906
File-backed pages:                       23821
Anonymous pages:                         152403
Compressions:                            356216
Decompressions:                          121241
Compressor Size:                         16403
Uncompressed Pages in Compressor:        49228
Largest process:   Chrome

[...]

Chrome <2a759438c2253e3baededaa0d13feb56>       166479           166479  200  [per-process-limit] (frontmost) (resume)

Upvotes: 17

Views: 39060

Answers (8)

parliament
parliament

Reputation: 22934

In my case the crashing was caused by using CSS filter: blur(2px) to create a colored "glow" effect.

I fixed it by creating the glow in photoshop and using a PNG file to render the glow on my website.

This not only fixed the crash but created a nicer, more even glow that also didn't re-render in strange ways when zooming and scrolling.

Upvotes: 0

anuj_io
anuj_io

Reputation: 2173

Sorry for just making a guesses but I see two potential causes in your stylesheet which could be resulting in crash

1.) Using data-url for background image rendering such as here

.github,.source {
background-image: url("data:image/svg+xml;charset=US-ASCII,%3Csvg%20width%3D%22100%22%20height%3D%22100%22%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%3E%3Cpath%20d%3D%22M85.714%2050q0%2014.007-8.175%2025.195t-21.122%2015.485q-1.507.279-2.204-.391t-.698-1.674v-11.775q0-5.413-2.902-7.924%203.181-.335%205.72-1.004t5.246-2.176%204.52-3.711%202.958-5.859%201.144-8.398q0-6.752-4.408-11.496%202.065-5.078-.446-11.384-1.563-.502-4.52.614t-5.134%202.455l-2.121%201.339q-5.19-1.451-10.714-1.451t-10.714%201.451q-.893-.614-2.372-1.507t-4.66-2.148-4.799-.753q-2.455%206.306-.391%2011.384-4.408%204.743-4.408%2011.496%200%204.743%201.144%208.371t2.93%205.859%204.492%203.739%205.246%202.176%205.72%201.004q-2.232%202.009-2.734%205.748-1.172.558-2.511.837t-3.181.279-3.655-1.2-3.097-3.488q-1.06-1.786-2.706-2.902t-2.762-1.339l-1.116-.167q-1.172%200-1.618.251t-.279.642.502.781.725.67l.391.279q1.228.558%202.427%202.121t1.758%202.846l.558%201.283q.725%202.121%202.455%203.432t3.739%201.674%203.878.391%203.097-.195l1.283-.223q0%202.121.028%204.967t.028%203.013q0%201.004-.725%201.674t-2.232.391q-12.946-4.297-21.122-15.485t-8.175-25.195q0-11.663%205.748-21.512t15.597-15.597%2021.512-5.748%2021.512%205.748%2015.597%2015.597%205.748%2021.512z%22%2F%3E%3C%2Fsvg%3E");
background-repeat: no-repeat;
}

2.) Also -webkit-transition could be the culprit. Read here for more https://stackoverflow.com/a/11833285/900132

Upvotes: 2

teewuane
teewuane

Reputation: 5734

Removing position: sticky; helped me and my mobile safari crashing issues. Not sure exactly why.

body:before{
    position:-webkit-sticky;
    position:sticky;
}

Upvotes: 0

lloiser
lloiser

Reputation: 1191

On my site it was caused by elements with the css property -webkit-backface-visibility: hidden

removing this property fixed all crashes!

see iOS: Multiple divs with -webkit-backface-visibility:hidden crash browser when zooming

Upvotes: 5

Ziggy
Ziggy

Reputation: 103

I just read this post and tried http://davidtheclark.github.io/scut/ on my iPad. Chrome crashes immediately, although sometimes shortly shows the home page. Safari renders the home page correct and many other pages, but clicking on the "about > installation" link at the left makes it crash right away (well, once it displayed OK, but clicking again crashed it). All of this is pretty consistent.

The errors are indeed due to LowMemory and it's the browser process that uses the most memory. The crashes happen at around 150000 pages (4KB/page? => 600MB???).

That being said, I'm afraid I don't have an answer to your question. Hope it helps at least a little bit.

Kind regards, /Sigiswald

Upvotes: 0

davidtheclark
davidtheclark

Reputation: 4676

I think I fixed it!

The problem, as suspected, was rendering/painting caused by CSS layout. At phone-size, I had been hiding the content of each entry until it was selected; and the method I had been using to hide them, and remove any trace of them from the layout, included position: absolute. I didn't initially use display: none because of typical concerns about wanting to not see content but keep it there, for various readers and reasons. I threw those concerns aside and changed the layout so that the entries were hidden with display: none and shown with display: block -- and that seems to have fixed the crashing.

I think the absolute positioning was stacking a huge amount of content in the corner of the screen, and although it wasn't visible, it was demanding memory.

What clued me in to trying this was an answer to another related question, linked to above by @tea_totaler: https://stackoverflow.com/a/14866503/2284669. It says:

What tends to help me a lot is to keep anything that is not visible at this time under display: none. This might sound primitive but actually does the trick. It's a simple way to tell the renderer of the browser that you don't need this element at this time and therefore releases memory. This allows you to create mile long vertical scrollers with all sorts of 3d effects as long as you hide elements that you are not using at this time.

I think that my other hiding method was not releasing memory, despite its other advantages (which were possibly irrelevant to this particular site anyway). I'm sure it became a problem only because the site was so long.

That's something to consider, though, when you want to hide an element: rendering/memory demands.

Upvotes: 14

Anachronist
Anachronist

Reputation: 1102

Your HTML markup has some errors (such as a div tag inside an h1 tag) that should be fixed before you try to analyze a crash.

I suggest you run it through an HTML validator, for example http://validator.w3.org/check?uri=http%3A%2F%2Fdavidtheclark.github.io%2Fscut%2F&charset=%28detect+automatically%29&doctype=Inline&group=0

The div inside h1 apparently caused a cascade of errors that the validator had to suppress to continue.

When I have browser crashing problems, HTML validation is always my first step. Then I try seeing what might be wrong with the javascript if correcting the HTML didn't help.

Upvotes: 1

tzengia
tzengia

Reputation: 362

I ran an audit with Chrome on the site. It suggested this:

Remove unused CSS rules (44)
44 rules (10%) of CSS not used by the current page.
css-built.min.css: 10% is not used by the current page. 


    audio, canvas, video  
    audio:not([controls])  
    [hidden]  
    abbr[title]  
    dfn  
    hr  
    mark  
    q  
    sub, sup  
    sup  
    sub  
    svg:not(:root)  
    figure  
    fieldset  
    legend  
    button[disabled], html input[disabled]  
    input[type=checkbox], input[type=radio]  
    input[type=search]  
    input[type=search]::-webkit-search-cancel-button, input[type=search]::-webkit-search-decoration  
    textarea  
    table  
    .older-docs  
    .older-docs>li  
    .older-docs>li:not(:last-child):after  
    *, :before, :after  
    fieldset  
    textarea  
    :not(pre)>code[class*=language-], pre[class*=language-]  
    :not(pre)>code[class*=language-]  
    .namespace  
    .token.regex, .token.important  
    .token.important  
    .older-docs  
    .changelog dt  
    .changelog>dt  
    .changelog>dt:after  
    .changelog>dd  
    .changelog-i-list  
    :target>.entry-body  
    .sub--h  
    .example--css.is-active  
    .preload .help-content-c  
    .help-content-c.is-active  
    .help-content.is-active

The task manager on Chrome shows that the page takes up about 2x as much total memory than other sites, such as stackoverflow and dropbox. I would recommend dividing up the features into separate pages instead of one long page. By separating the features it would improve the server's efficiency and the browser's load time and memory usage. There would be less JavaScript and CSS running on each page and smaller amounts of data would be sent from the server. Having all the features on the home page is inefficient. For example, if a user only needed to look up how to make a Font Icon Label they would have to load other sections of the page that are not needed and take up memory.

Upvotes: 3

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