Error with clicking

I have a sprite that when you click on it, it closes the game, but theres an error that says "Assets/ClickyThingy - Copy.js(5,18): BCE0017: The best overload for the method 'UnityEngine.Application.Quit is not compatible with the argument list ‘(String)’.

here’s my code

 #pragma strict
    function OnMouseDown()

Application.Quit doesn’t accept any parameter, it quits the game and is not meant to unload a level. As already said here, this function works only in the build and not when you play in the editor.