Iphone – Remove textarea inner shadow on Mobile Safari (iPhone)

This seems to be the right thing to do, according to the Safari HTML Reference:

<meta name="format-detection" content="telephone=no">

If you disable this but still want telephone links, you can still use the "tel" URI scheme.

Here is the relevant page at Apple's Developer Library.

On iOS 5 and later:

input {
  border-radius: 0;
}

input[type="search"] {
  -webkit-appearance: none;
}

If you must only remove the rounded corners on iOS or otherwise for some reason cannot normalize rounded corners across platforms, use input { -webkit-border-radius: 0; } property instead, which is still supported. Of course do note that Apple can choose to drop support for the prefixed property at any time, but considering their other platform-specific CSS features chances are they'll keep it around.

On legacy versions you had to set -webkit-appearance: none instead:

input {
    -webkit-appearance: none;
}