Internet Explorer will not remove an input’s border when using the border: none CSS property. In order to achieve this effect for other major browsers as well as for IE you need to also add border-color: transparent.
Update April 2010
As noted in allex’s comment below there is a simpler solution:
input{
border:0
}
I have tested this out and it works fine on all the major browsers (IE 6+, Firefox 3+, Safari 4+, Chrome and Opera).
Example
See a working example on the demo page.
HTML markup
<input type="text" value="textInput" />
CSS
input{
border: none;
border-color: transparent;
}
Side effects
Be careful when using border-color: transparent with border: none because they will impact the input’s box model by removing the border’s dimensions.
This will alter the input’s relationship, like vertical positioning, with surrounding elements.

[...] Using the border: none property will remove the input’s border from most browsers but not for Internet Explorer. In order to fix IE’s input border you need to also add border-color: transparent. More about this issue on IE’s buggy border property in this article. [...]
[...] Border: none not working on text input in Internet Explorer [...]
thank you so much man
just need set border:0;
it works great!
In my css i had a send button (div:hover with changing background)
that also didnt work, but now with this input:0 the default IE button is replaced for my nice css button!
Merci !
thanks a lot
THANK YOU!!!!!
Perfect! Thanks!
Thanx a lot