

I think a better way would be to make use of the title-attribute instead of catching alert-function, as the plugin does
#dhtmltooltip{
font:12px arial,sans-serif;
line-height: 1.3em;
color: #333;
position: absolute;
width: 200px;
border: 3px solid #999;
padding: 5px;
background-color: #ffc;
visibility: hidden;
z-index: 100;
}