The Design And Implementation Of Embedded JavaScript Interpreter On Set Top Box

At the present stage, the Digital TV is being developed rapidly in the global range. Various kinds of research about the technology of the DTV are being studied in an all-round way. People are no longer satisfied with passive watching TV for information, but have higher demands for the interactive serves of broadband; they also want to browse the various information of the Internet. It is not enough if the embedded browser of STB can only support static HTML pages, because people want more dynamic and interactive serves. JavaScript is the language to meet this demand. Thus it is a obvious trend for the embedded devices to support JavaScript.This paper constructs the architecture of the embedded JavaScript interpreter system according to the feature of JavaScript language and the actual demand of the embedded browser. The interpreter system is composed of two subsystems: compiler and interpreter. The main idea of this paper is the design and implementation of lexical scanner, syntax parser and execute module. The compiler/interpreter model is based on a self-defined intermediate code. The design of intermediate code is analyzed from 3 points: the represent and domain of variable, the design of object model and the description of intermediate code. Then based on the intermediate code, the execute engine complete the execution of all statement, including the top-down operator precedence algorithm, resource management and the interaction with browser.In the end, this paper introduces the application of embedded JavaScript interpreter in data broadcasting from 4 aspects: the interactive TV middleware, IPTV, AJAX and Flash.