Sweet Javascript Suggest Box

<style type="text/css">
.suggestions { border: 1px solid gray; background-color: White; position: absolute; padding: 2px; font-family: Arial; font-size: small; visibility: hidden; }
</style>
<script type="text/javascript">
document.onclick = clickHandler;
function clickHandler() {
var div = document.getElementById("suggestions");
if (div.style.visibility == "collapse") {
div.style.visibility = "visible";
} else {
div.style.visibility = "hidden";
}
}
function showSuggestions() {
var div = document.getElementById("suggestions");
if (div.style.visibility != "visible")
div.style.visibility = "collapse";
}
function setSuggestion(span) {
<%
TextBox tb = (TextBox)dvStudent.FindControl("TextBox1");
String id = (tb != null) ? tb.ClientID : "TextBox1";
%>
var tb = document.getElementById('<%= id %>');
tb.value = span.innerHTML;
}
</script>

<asp:TextBox ID="TextBox1" runat="server" onclick="showSuggestions()" ></asp:TextBox>
<div id="suggestions" class="suggestions">
<span style="display:block;width:100%" onmouseover="this.style.backgroundColor='LightBlue';" onmouseout="this.style.backgroundColor='White';" onclick="setSuggestion(this);">A Suggestion</span>
</div>