I have one html page and I added the button in nav bar. Is there a way to make the button hover?

So I have all my other buttons hovering but that

Hi!

Add to CSS Stylesheet:

Code:

a.mainmenu{
-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=80)";
filter: alpha(opacity=80);
-khtml-opacity: 0.8;
-moz-opacity: 0.8;
opacity: 0.8;
}

a.mainmenu:hover{
-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=100)";
filter: alpha(opacity=100);
-khtml-opacity: 1.0;
-moz-opacity: 1.0;
opacity: 1.0;
}

No, I mean the hover button, I have only images on navbar and I would like to get my own button to my html page have an hover effect