Hi,
1st Problem:
write below code at button click event after executing your code:
ScriptManager.RegisterStartUpScript(this,this.GetType(),"MyScript", "alert('Inserted Successfully');", true);
2nd Problem
set style of table
style="display:block"
then call a JS function onMouseOver event
in JS
if(document.getElementById('TableID').style.display == 'block')
{
document.getElementById('TableID').style.display = 'none';
}
else if(document.getElementById('TableID').style.display == 'none')
{
document.getElementById('TableID').style.display = 'block';
}