JavaScript Interpreter Research Articles

Using JavaScript in web design

JavaScript was created to bring a web page to life. Scripts are programs written in JavaScript. Each script is connected directly to HyperText Markup Language (HTML) in any browser and is immediately executed when the web page is loaded. JavaScript scripts are written in plain text that does not require special training, which is why JavaScript is very different from the Java programming language, to which it is very similar. A special interpreter program allows JavaScript to be used not only in the browser but anywhere, and therefore the process of executing script commands is called “interpretation.” The interpreter executes the program’s JavaScript ource code (script) “as is” in browsers. Modern interpreters convert JavaScript to machine code before execution, optimize it, and only then perform it. Because of this, JavaScript is very fast. All known browsers have a JavaScript interpreter built into them, which is why they can execute scripts on the page. However, JavaScript can be used outside of the browser. This is a full-fledged language, with programs that can be run on a server and even on consumer electronic devices, if they have the appropriate interpreter installed. This article presents various JavaScript applications, used by the author, embedded in HTML files that allow a web designer to make a text animation presentation on a web page, to make a slide show, to create a questionnaire with ready-made answers so that the user reading the web page can easily master the necessary material contained in the questionnaire, to conduct an exam with the user on any topic of interest to him or her in a multitask mode with assessments of the exam results and a table of correct answers, place scientific applications on the web page, for example, a table of chemical elements by Mendeleev with printing of all parameters of a chemical element at the request of the user or calculators that the user can use online. The author has managed to build HTML using JavaScript that allows displaying beautiful Java applets accompanied by a banner, designed as a Java applet, contained within a moving window that expands from the left end and moves to the right end at the top of the web page.

인터프리터 기반 교육용 로봇을 위한 분산 제어 시스템 개발

In this study, a distributed control system for interpreter-based educational robot, which has a unique feature of stacking several additional modules, is developed. The central control unit uses a I²C bus to manage and control the additional modules attached to the robot. The program created by user is transferred to the base module via Bluetooth and executed by a JavaScript interpreter in the central control unit of the module. The multitasking feature of the robot allows the central control unit to execute the user program and run the background program that manages the modules. A method using timer-based scheduler to maintain the minimum required operating frequency of the background program is proposed. The effectiveness of the proposed method is evaluated experimentally. The results indicate that the proposed method guarantees the minimum required operating frequency irrespective of computational complexity of the user program.

Test-driven development for generated portable Javascript apps

With the advent of HTML 5, we can now develop rich web apps in Javascript that rival classical standalone apps. Nevertheless, developing in Javascript is still challenging and error prone because of the language's ambiguous semantics and quirks. In this paper, we advocate that the popular solution of using another language with better semantics and constructs is not enough. Developers should be provided with an IDE that eases the integration of Javascript libraries and enables testing an application across the many available Javascript interpreters. We introduce PharoJS, 1 an infrastructure that allows Test-Driven Development (TDD) in Pharo Smalltalk of applications that ultimately run on a Javascript interpreter. PharoJS makes it possible to run interactive tests within the Pharo IDE, so as to fully exploit the debugging and development environment, while UI and libraries reside on the Javascript side. • Produces fast, standard, Javascript code preserving Smalltalk semantics. • Javascript debugging by leveraging the Pharo Smalltalk IDE. • Final Javascript applications for deployment are fully standalone. • Same test suite runs on multiple JS interperters to verify portability.

Neverlang: A framework for feature-oriented language development

Reuse in programming language development is an open research problem. Many authors have proposed frameworks for modular language development. These frameworks focus on maximizing code reuse, providing primitives for componentizing language implementations. There is also an open debate on combining feature-orientation with modular language development. Feature-oriented programming is a vision of computer programming in which features can be implemented separately, and then combined to build a variety of software products. However, even though feature-orientation and modular programming are strongly connected, modular language development frameworks are not usually meant primarily for feature-oriented language definition. In this paper we present a model of language development that puts feature implementation at the center, and describe its implementation in the Neverlang framework. The model has been evaluated through several languages implementations: in this paper, a state machine language is used as a means of comparison with other frameworks, and a JavaScript interpreter implementation is used to further illustrate the benefits that our model provides.

Information flow tracking meets just-in-time compilation

Web applications are vulnerable to cross-site scripting attacks that enable data thefts. Information flow tracking in web browsers can prevent communication of sensitive data to unintended recipients and thereby stop such data thefts. Unfortunately, existing solutions have focused on incorporating information flow into browsers’ JavaScript interpreters, rather than just-in-time compilers, rendering the resulting performance noncompetitive. Few users will switch to a safer browser if it comes at the cost of significantly degrading web application performance. We present the first information flow tracking JavaScript engine that is based on a true just-in-time compiler, and that thereby outperforms all previous interpreter-based information flow tracking JavaScript engines by more than a factor of two. Our JIT-based engine (i) has the same coverage as previous interpreter- based solutions, (ii) requires reasonable implementation effort, and (iii) introduces new optimizations to achieve acceptable performance. When evaluated against three industry-standard JavaScript benchmark suites, there is still an average slowdown of 73% over engines that do not support information flow, but this is now well within the range that many users will find an acceptable price for obtaining substantially increased security.

Bootstrapping a self-hosted research virtual machine for JavaScript

JavaScript is one of the most widely used dynamic languages. The performance of existing JavaScript VMs, however, is lower than that of VMs for static languages. There is a need for a research VM to easily explore new implementation approaches. This paper presents the Tachyon JavaScript VM which was designed to be flexible and to allow experimenting with new approaches for the execution of JavaScript. The Tachyon VM is itself implemented in JavaScript and currently supports a subset of the full language that is sufficient to bootstrap itself. The paper discusses the architecture of the system and in particular the bootstrapping of a self-hosted VM. Preliminary performance results indicate that our VM, with few optimizations, can already execute code faster than a commercial JavaScript interpreter on some benchmarks.

AGUIA: autonomous graphical user interface assembly for clinical trials semantic data services

BackgroundAGUIA is a front-end web application originally developed to manage clinical, demographic and biomolecular patient data collected during clinical trials at MD Anderson Cancer Center. The diversity of methods involved in patient screening and sample processing generates a variety of data types that require a resource-oriented architecture to capture the associations between the heterogeneous data elements. AGUIA uses a semantic web formalism, resource description framework (RDF), and a bottom-up design of knowledge bases that employ the S3DB tool as the starting point for the client's interface assembly.MethodsThe data web service, S3DB, meets the necessary requirements of generating the RDF and of explicitly distinguishing the description of the domain from its instantiation, while allowing for continuous editing of both. Furthermore, it uses an HTTP-REST protocol, has a SPARQL endpoint, and has open source availability in the public domain, which facilitates the development and dissemination of this application. However, S3DB alone does not address the issue of representing content in a form that makes sense for domain experts.ResultsWe identified an autonomous set of descriptors, the GBox, that provides user and domain specifications for the graphical user interface. This was achieved by identifying a formalism that makes use of an RDF schema to enable the automatic assembly of graphical user interfaces in a meaningful manner while using only resources native to the client web browser (JavaScript interpreter, document object model). We defined a generalized RDF model such that changes in the graphic descriptors are automatically and immediately (locally) reflected into the configuration of the client's interface application.ConclusionsThe design patterns identified for the GBox benefit from and reflect the specific requirements of interacting with data generated by clinical trials, and they contain clues for a general purpose solution to the challenge of having interfaces automatically assembled for multiple and volatile views of a domain. By coding AGUIA in JavaScript, for which all browsers include a native interpreter, a solution was found that assembles interfaces that are meaningful to the particular user, and which are also ubiquitous and lightweight, allowing the computational load to be carried by the client's machine.

SPUR

Tracing just-in-time compilers (TJITs) determine frequently executed traces (hot paths and loops) in running programs and focus their optimization effort by emitting optimized machine code specialized to these traces. Prior work has established this strategy to be especially beneficial for dynamic languages such as JavaScript, where the TJIT interfaces with the interpreter and produces machine code from the JavaScript trace. This direct coupling with a JavaScript interpreter makes it difficult to harness the power of a TJIT for other components that are not written in JavaScript, e.g., the DOM implementation or the layout engine inside a browser. Furthermore, if a TJIT is tied to a particular high-level language interpreter, it is difficult to reuse it for other input languages as the optimizations are likely targeted at specific idioms of the source language. To address these issues, we designed and implemented a TJIT for Microsoft's Common Intermediate Language CIL (the target language of C#, VisualBasic, F#, and many other languages). Working on CIL enables TJIT optimizations for any program compiled to this platform. In addition, to validate that the performance gains of a TJIT for JavaScript do not depend on specific idioms of JavaScript that are lost in the translation to CIL, we provide a performance evaluation of our JavaScript runtime which translates JavaScript to CIL and then runs on top of our CIL TJIT.

Grammar-based whitebox fuzzing

Whitebox fuzzing is a form of automatic dynamic test generation, based on symbolic execution and constraint solving, designed for security testing of large applications. Unfortunately, the current effectiveness of whitebox fuzzing is limited when testing applications with highly-structured inputs, such as compilers and interpreters. These applications process their inputs in stages, such as lexing, parsing and evaluation. Due to the enormous number of control paths in early processing stages, whitebox fuzzing rarely reaches parts of the application beyond those first stages. In this paper, we study how to enhance whitebox fuzzing of complex structured-input applications with a grammar-based specification of their valid inputs. We present a novel dynamic test generation algorithm where symbolic execution directly generates grammar-based constraints whose satisfiability is checked using a custom grammar-based constraint solver. We have implemented this algorithm and evaluated it on a large security-critical application, the JavaScript interpreter of Internet Explorer 7 (IE7). Results of our experiments show that grammar-based whitebox fuzzing explores deeper program paths and avoids dead-ends due to non-parsable inputs. Compared to regular whitebox fuzzing, grammar-based whitebox fuzzing increased coverage of the code generation module of the IE7 JavaScript interpreter from 53% to 81% while using three times fewer tests.