setNativeProperty not working with webView

I’m trying to set these properties in a webView:

webView:setNativeProperty( “allowFileAccessFromFileURLs”, true )
webView:setNativeProperty( “allowUniversalAccessFromFileURLs”, true )

But I get this messages:
Unable to setNativeProperty allowFileAccessFromFileURLs

Are these property names correct? Am I missing something else that has to be configured?