Multiple (different) Usercontrol and conflicts

say i have this

Usercontrol path.....mywebsite/controls/Mycontrol1/Control1.ascx
Code within this ascx is like this...
1 <style type="text/css">
2 .divPeriodCss
3 {
4 some CSS stuff
5 }
6 <style>
7
8 <div id="divPeriod runat="server>
9 .....some more code
10
11 <div>
12
13 <script language="javascript" type="text/jav ...