Build a development version of the player.
A development build includes debug symbols and enables the Profiler. (To profile a webplayer you need to have the development version of the web player installed. The unity3d file can be profiled only when the development webplayer is active.)
Note that a development build of a webplayer means that the unity3d file created is not LZMA compressed.
See Also: BuildPipeline.BuildPlayer.