CodePen

HTML

            
              
            
          
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CSS

            
              
            
          
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Must be a valid URL.
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JS

            
              > function f() {return this;}
> f()
true
> f.call() == window
true
> f.call("hello") // actually creates a string object
[object String]
> o = f.call({a:1})
> o.a
1
            
          
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