HTTP_ACCEPT - Reliabilty?

I'm using Flash very often within websites. Like you know, sometimes the user doesn't have the Flash-plug-in so I was wandering if I could depend on this $_SERVER['HTTP_ACCEPT'] variable to look for "shockwave-flash". If found, the visitor has Flash-plugging, if not, he doesn't. So my question really is, can I base my Flash-detection on this global variable or is too uncertain? (e.g. when the user is using Netscape, Opera etc., Linux, Mac etc.) Regards, Sumarlidi E. Dadason SED - Graphic Design _________________________________ E-mail: sed@sed.is website: www.sed.is