ListBox4.aspx font size:
<head>
<title>Setting Multiple Selections in a List Control</title>
<link rel="stylesheet" href="/shared/netdemos.css">

<script language="C#" runat="server">
void setSelected ( object src, EventArgs e ) {
   int i = 0;
   foreach ( ListItem item in myList.Items ) {
      if ( i % 2 == 0 ) item.Selected = true;
      i++;
   }
   getSelected ( myList, null );
}

void getSelected ( object src, EventArgs e ) {
   string s = "Selected items:<br>";
   foreach ( ListItem item in myList.Items ) {
      if ( item.Selected ) {
         // list the selected item
         s += item.Text + "<br>";
      }
   }
   msg.Text = s;
}

void clearSelected ( object src, EventArgs e ) {
   foreach ( ListItem item in myList.Items ) {
      item.Selected = false;
   }
   msg.Text = "No selected item";
}
</script>
</head>

<body>
<!-- #include virtual="~/shared/top.inc -->
<div class="header"><h2>Setting Multiple Selections in a List Control</h2></div>

<!-- #include virtual="~/shared/viewsrc_top.inc" -->
<hr size=1 width=92%>
<form runat="server">

   <asp:ListBox id="myList" selectionmode="multiple" width=100 runat="server">
      <asp:listitem value="earth.gif" text="Earth"/>
      <asp:listitem value="jupiter.gif" text="Jupiter"/>
      <asp:listitem value="mars.gif" text="Mars"/>
      <asp:listitem value="mercury.gif" text="Mercury"/>
      <asp:listitem value="neptune.gif" text="Neptune"/>
      <asp:listitem value="pluto.gif" text="Pluto"/>
      <asp:listitem value="saturn.gif" text="Saturn"/>
      <asp:listitem value="uranus.gif" text="Uranus"/>
      <asp:listitem value="venus.gif" text="Venus"/>
   </asp:ListBox>

   <asp:button Text="Select" onClick="setSelected" runat="server" />
   <asp:button Text="Clear" onClick="clearSelected" runat="server" />

   <p><asp:Label id="msg" runat="server" />

</form>
<hr size=1 width=92%>
<!-- #include virtual="~/shared/viewsrc.inc" -->

</body>
</html>