The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>).

I have inherited asp.net code in which javascript is in the <head> section of a aspx page. I am getting the error  at
var javascriptVar = '<% csharpClass = new CSharpClass(); connStr= csharpClass.GetValue();Response.Write(connStr);%>';
How can I resolve this error?
 
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