What browsers support JavaScript entities?

As mentioned, only Netscape 4 supports JavaScript entities. The closest feature supported in modern IE browsers such as IE6 is dynamic properties.

Think of JavaScript entities as an "enhancement" to HTML attributes, not replacement. And since JavaScript entities are simply HTML attribute values, browsers that don't support them (such as IE) will simply ignore the declaration. These entities can comfortably co-exist with regular HTML attributes so browsers that support entities take advantage of it, while browsers that don't simply move on with their regular lives. All you have to do is declare an HTML attribute twice- the first using a regular HTML value (for non JavaScript entity supporting browsers), and following that, a JavaScript entity value for those that do support this nifty feature. For example:

<table width="80%" width="&{tablewidth };">