Q:

Underline ie6-bug. Inline element in  tag

There is a markup: 
<a href="#">
    lorem ipsum<span>15</span>
</a>

There are styles:
a{
    text-decoration: underline;
}

a span{
    background: #fff;  //To clean the bottom underlining under <span>
}

Works in all interesting me browsers. Except IE6. The bottom underlining under <span> remains.
How to solve this problem without changing a markup.

a span{
    text-decoration: none;
}

Does not work.

A:

Try changing your CSS to this:
a span {
    background: #fff;
    display: inline-block;
}

Despite what others have posted, text-decoration: none; does NOT work.

