How can I disable the clear button that IE10 inserts into textboxes?

Question

How can I disable the new functionality in Internet Explorer 10 that shows a little \'x\' in a textbox when it\'s focused and I have content in it?

Answer 1

Note that the style and CSS solutions don't work when a page runs in compatibility view. I'm assuming that this is because the clear button was introduced after IE7, and so the IE7 renderer used in compatibility view doesn't see ::-ms-clear as a valid style heading.