<asp:Button ID="tianjia" runat="server" Text="" Visible=false style=" background:url(/images/dincan/an1.jpg); width:90px; height:30px; background-position: center center; border:0px; cursor:pointer;"
onclick="tianjia_Click" OnClientClick="return check()" />
OnClientClick="return check()"
<script type="text/javascript">javascript
function check()
{
alert('ceshi');
return false;
}java
</script>url