Disable auto correct in Safari text input

You need to add spellcheck="false" to your input.

<input autocomplete="off" autocorrect="off" autocapitalize="off" type="text" name="url" placeholder="Enter a web address" spellcheck="false">

Fiddle

If you have to do this with jQuery, you'll need to leave the quotes off of false.

$(this).prop("spellcheck", false); // this works

$(this).prop("spellcheck", "false"); // this does NOT properly set the property

(I would have put this in a comment, but I don't have a high enough rep yet)