wave84, your question betrays your ignorance. in all software design, there is a trade off between memory use, speed, complexity. as the market expectation has evolved, the best approach also changes. it would have been a mistake for someone to invest this much in javascript performance before people were attempting complex site development using heavy javascript libraries. A few years ago, the main use of javascript was running a half dozen lines of javascript when someone pressed a button or hovered over an element. in that context, a simple interpreter would get the job done before a javascript compiler could begin actually running the code.