How to remove background of <tooltip>

I am having a <tooltip>. Inside that, I am having a <button>. But this shows a backgroun开发者_StackOverflowd around button. How to remove it? I want just the button to appear as if it is just a standalone button floating.

The <tooltip> element doesn't have a predefined background, at least not in the default Windows theme. Instead it seems to use the default background defined by the operating system. You can disable this behavior by changing -moz-appearance CSS property. Setting background as well won't harm, other themes might defined it:

-moz-appearance: none;
background: transparent;

Use CSS to make tooltip's background transparent.