javascript - If statement being ignored -

My if statement is being ignored. I am very new to coding.
I think that I'm missing semicolon or a scribble or something like a little.

  & lt; Script type = "text / javascript" & gt; Function shadow () (if (document.getElementById ("nav-wrap-2") style. Opacity = '.5') {document.getElementById ("nav-wrap-2"). Style.opacity = '0'; Document.getElementById ("Content-wrap"). Style.marginLeft = '250px';}}  Edit   
 If: I was the right solution in the statement == is changing, although this whole problem has not been resolved if I had to get rid of quotation around '.5' in the statement. Derp.   
 
 
 You must use" == "to compare  
" = "In JavaScript Nment will perform.