button runs checkbox doesn't

Hi, I'm working on a webpage, and I'm trying to run some server side code. The problem is that I need to use a checkbox to toggle something. When I try to run the code it will not work. However when I do it using a button it works perfectly. Here is the button and checkbox code:
Check box = does not work
<asp:CheckBox ID="CheckBox1" runat="server" oncheckedchanged="CheckBox1_CheckedChanged" Text="Third Floor" /> Butotn = Works
<asp:button ID="CheckBox1" runat="server" oncheckedchanged="CheckBox1_CheckedChanged" Text="Third Floor" />
They are the same exact lines of code except I switch "checkbox" and "button"
Any help would be greatly appreciated. Thanks.
 
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