mobile safari and viewport

Apple’s mobile browser is great, but the viewport meta tag is kind of a hash. There seems to be two conflicting ways to hint to the iPhone or iPad how big to draw things.

  1. width and height. Tells the browser this content is going to render best at a certain width, so render it to that size. width=device-width or width=320 is one way to tell the iPhone not to scale at all. width=600 or the like often solves the problem of stuff looking too small on the iPhone, while still letting it scale. If you set a small width the iPad will scale content up, making it bigger.
  2. initial-scale, minimum-scale, maximum-scale. Gives an explicit scaling factor. The user can override this (unless you disable it).

What’s confusing is if you set both a width and scaling behaviour: which takes precedence?

Mike suggested what seems to work well for maps is setting initial-scale to 1.0 and maximum-scale to 1.0. This keeps Safari from doing its own scaling on the page at all. Even better, when you rotate the device it doesn’t try to scale the width to match the old view; instead it just loads some stuff that was previously off-screen. The only drawback is this effectively sets the width to 320px on an iPhone, you no longer get any in-browser scaling.

What I really want is no scaling at all on the iPad, and 1.5 scaling on the iPhone. I can’t figure out a way to do that without changing the tags depending on what device loaded the page.