The user-select CSS property is great for disabling text selection on elements. Currently, it is mostly implemented by renderer-specific tags like '-webkit-user-select', '-moz-user-select', and '-khtml-user-select', with 'user-select' itself being ignored. It'd be nice to have support for detecting this in Modernizr (at least, at some point -- possibly when the majority of browsers finally recognize 'user-select' directly, although I'm not familiar enough with general Modernizr policy on the issue of browser-specific CSS).

Right now, I just use draganddrop for this purpose, because I figure that's a pretty good prereq for "proper" draganddrop, so it's good enough for me.