diff --git a/syntax_checkers/javascript/jsl.vim b/syntax_checkers/javascript/jsl.vim
index 36c7efc5..a4a68ae1 100644
--- a/syntax_checkers/javascript/jsl.vim
+++ b/syntax_checkers/javascript/jsl.vim
@@ -12,8 +12,16 @@ if !exists("g:syntastic_javascript_jsl_conf")
     let g:syntastic_javascript_jsl_conf = ""
 endif
 
+function s:ConfFlag()
+    if !empty(g:syntastic_javascript_jsl_conf)
+        return "-conf " . g:syntastic_javascript_jsl_conf
+    endif
+
+    return ""
+endfunction
+
 function! SyntaxCheckers_javascript_GetLocList()
-    let makeprg = "jsl " . g:syntastic_javascript_jsl_conf . " -nologo -nofilelisting -nosummary -nocontext -process ".shellescape(expand('%'))
+    let makeprg = "jsl " . s:ConfFlag() . " -nologo -nofilelisting -nosummary -nocontext -process ".shellescape(expand('%'))
     let errorformat='%W%f(%l): lint warning: %m,%-Z%p^,%W%f(%l): warning: %m,%-Z%p^,%E%f(%l): SyntaxError: %m,%-Z%p^,%-G'
     return SyntasticMake({ 'makeprg': makeprg, 'errorformat': errorformat })
 endfunction