function showToolTip() {
document.getElementById("tooltip").textContent = "I am tooltip text";
}
function hideToolTip() {
document.getElementById("tooltip").textContent = "";
}
<body>
<div onmouseover="showToolTip()" onmouseout="hideToolTip()" style="position: absolute;width: 84.66px;height: 18px;"></div>
<input id="theButton" type="button" value="I am disabled" disabled="disabled">
<br>
<span id="tooltip"></span>
</body>