How to copy data of one textbox to 2nd and make 2nd textbox readonly?

hi i have the following form in the asp.net
<form id="myform" runat="server"> <asp:TextBox ID="local" runat="server"></asp:TextBox> <asp:TextBox ID="main" runat="server"></asp:TextBox> <asp:CheckBox ID="chekcme" runat="server" /> </form> and i want to make readonly and copy the text from the local textbox when the checkbox is chekced, using jquery.
how can i write this script in jquery.
Help heighly appriciated

Regards
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