Why won't my viewport tag properly use device width (no zoom) on most mobile devices?
UPDATE 12/2020: Seeing as this post still gets activity, I must stress that there are no answers here that apply to modern web development. In fact, almost all of the answers here would put your website in a precarious situation when it comes to accommodating those with disabilities. The only thing your responsive website should include in the head tag is:
<meta name="viewport" content="width=device-width, initial-scale=1">
Much more than just UX is at risk if you attempt to lock users into a specific scale (such as lawsuits or even government fines).
-- CONTINUE AT YOUR OWN RISK --
UPDATE 03/2019: This Q&A still gets some activity, nearly 5 years my question came up. Please note this problem was due in part to more common irregularities in older mobile devices at THAT time. With today's browsers and devices, fiddling with viewport scalability would be a shoe-horn fix to a bigger problem which is likely a problem in either your CSS or possibly your markup.
I've built a dozen responsive sites and have never experienced this problem. Basically, I'm using the meta tag for viewport with width=device-width, but iPhone and Android devices are still zooming. For some reason, I don't have this problem on Windows phones.
Here is an excerpt from the head html:
<meta name="viewport" content="width=device-width, initial-scale=1" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
Here is the HTML for the main wrappers (note the outermost div is added from jquery.mobile:
<body class="html front logged-in no-sidebars page-node mobile-detect-class ismobiledevice" >
<div data-role="page" data-url="/?mobile_switch=mobile" tabindex="0" class="ui-page ui-body-c ui-page-active" style="min-height: 568px;">
<div class="container">
</div>
</div>
</body>
And here is the main wrapper CSS:
html,body { margin: 0; padding: 0; background-color: #d5d5d5; font-family: 'HelveticaNue', Arial; }
body {background: transparent none no-repeat 50% 0; min-height:100%; height:auto; background-size: auto 100%; width:auto;}
body > div {width: 100%; height: auto; }
.container { background: #fff none no-repeat 50% 0; margin-bottom: 20px; width:100%; position:relative;}
Bootstrap is also being loaded prior to the stylesheet.
I have tried a number of different things already including:
- Removing jquery.mobile
- Removing bootstrap
- Updating bootstrap to the latest version
- Changing the viewport tag to the following:
- width=device-width, initial-scale=1.0
- width=device-width, initial-scale=1.0, user-scalable=no
- width=device-width, initial-scale=1.0, user-scalable=0
- width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0
- Adjusting various CSS properties related to width/max-width
I am completely out of ideas and seem to have exhausted anything new I can find / try via google. I would greatly appreciate any help you can provide!
Answer
After much testing and continued searching, I came up with a fix that seems to be very effective. Another solution I saw to a similar problem proposed the following:
<meta name="viewport" content="width=640, initial-scale=.5, user-scalable=no" />
This, at first, seemed like a decent solution as it worked on most phones. It bugged me a little bit though because it obviously isn't geared specifically towards working with any device width. That answer can be found here:
Android viewport setting "user-scalable=no" breaks width / zoom level of viewport
This solution worked on most mobile devices, but on some it was ineffective causing the display to be using incorrect zoom.
I believe the reason why the solution above is not effective is because not all mobile devices use a base 320 for zoom. So when device-width isn't working, this causes the constraints to be inconsistent.
I tried a bunch of different things, but then ultimately tried the following which (so far) seems highly effective:
<meta name="viewport" content="width=device-width, initial-scale=0.5, user-scalable=no">
I believe the difference in this tag is that it tells the device to use it's native dimensions, but then adds a scale factor that tells it to not zoom in as much as it would normally.
I never was able to find any CSS adjustments that solved the problem, and I welcome any other answers in the future that may add further clarification to the problem/solution.
One other thing I'd like to add, is that an alternative meta tag that may be more effective for larger devices (tablets, which the site in this problem was not designed for), may be to set maximum scale instead of using user-scalable. Like this:
<meta name="viewport" content="width=device-width, initial-scale=0.5, maximum-scale=0.5">
EDIT / Update 2018:
This question still gets quite a few hits even though it's a very dated problem. Certainly in hindsight and after much more experience with responsive, I can say that both the initial problem and the solutions were based around stop-gap issues that resulted from poorly constructed responsive CSS and HTML.
While the answers here may help future visitors solve for issues when it comes to retro-fitting more dated code, I would highly recommend that any new development conform to the latest in responsive standards. If your markup and CSS conforms, there are very few reasons why you would ever not want the standard meta for viewport in responsive (below):
<meta name="viewport" content="width=device-width, initial-scale=1">