css - Form padding differences in Firefox and Opera/Chrome/IE

Question

I'm having a problem with the padding in my form on my website. If I've set a height/width to a form element and then adds a padding to it. In all browsers I've tried, except Firefox, the padding is added to the height/width.

If I have a input with 200 in width and 20px in height. and padding at 5 (all ways), the sum and total width and height would be 210px and 30px, but in Firefox it is 200px and 20px.

How do I work my way around this?

Answer 1

Give the input this CSS:

box-sizing: border-box;

You can read more about box-sizing on QuirksMode, the W3C spec, and MDN. Here is its browser support. Use the prefixes -moz- or -webkit- if required by your target browsers.

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This answer had previously suggested the value initial, which I had found by using the up/down arrow keys in the Chrome Web Inspector. But it turns out that initial is a CSS keyword, applicable to any property, that represents the initial value of the property – the browser’s default value. initial is less safe than explicitly naming which box model to use. If box-sizing: initial were specified and a browser’s default value for box-sizing changed, the input’s padding could break again.