Over the last few years, the complexity of web applications has increased to provide more dynamic web applications to users. The drawback of this complexity is the growing number of errors in the front-end applications. In this paper, we present BikiniProxy, a novel technique to provide self-healing for the web. BikiniProxy is designed as an HTTP proxy that uses five self-healing strategies to rewrite the buggy HTML and Javascript code. We evaluate BikiniProxy with a new benchmark of 555 reproducible Javascript errors, DeadClick. We create DeadClick by randomly crawling the Internet and collect all web pages that contain Javascript errors. Then, we observe how BikiniProxy heals those errors by collecting and comparing the traces of the original and healed pages. To sum up, BikiniProxy is a novel fully-automated self-healing approach that is specific to the web, evaluated on 555 real Javascript errors, and based on original self-healing rewriting strategies for HTML and Javascript.
Context: Client-side JavaScript is widely used in web applications to improve user-interactivity and minimize client-server communications. Unfortunately, web applications are prone to JavaScript faults. While prior studies have demonstrated the prevalence of these faults, no attempts have been made to determine their root causes and consequences. Objective: The goal of our study is to understand the root causes and impact of JavaScript faults and how the results can impact JavaScript programmers, testers and tool developers. Method: We perform an empirical study of 317 bug reports from 12 bug repositories. The bug reports are thoroughly examined to classify and extract information about the fault's cause (the error) and consequence (the failure and impact). Result: The majority (65 ) of JavaScript faults are DOM-related, meaning they are caused by faulty interactions of the JavaScript code with the Document Object Model (DOM). Further, 80 of the highest impact JavaScript faults are DOM-related. Finally, most JavaScript faults originate from programmer mistakes committed in the JavaScript code itself, as opposed to other web application components such as the server-side or HTML code. Conclusion: Given the prevalence of DOM-related faults, JavaScript programmers need development tools that can help them reason about the DOM. Also, testers should prioritize detection of DOM-related faults as most high impact faults belong to this category. Finally, developers can use the error patterns we found to design more powerful static analysis tools for JavaScript. Client-side JavaScript is widely used in web applications to improve user-interactivity and minimize client-server communications. Unfortunately, JavaScript is known to be error-prone. While prior studies have demonstrated the prevalence of JavaScript faults, no attempts have been made to determine their causes and consequences. The goal of our study is to understand the root causes and impact of JavaScript faults and how the results can impact JavaScript programmers, testers and tool developers. We perform an empirical study of 502 bug reports from 19 bug repositories. The bug reports are thoroughly examined to classify and extract information about each bug' cause (the error ) and consequence (the failure and impact ). Our results show that the majority (68 percent) of JavaScript faults are DOM-related , meaning they are caused by faulty interactions of the JavaScript code with the Document Object Model (DOM) . Further, 80 percent of the highest impact JavaScript faults are DOM-related. Finally, most JavaScript faults originate from programmer mistakes committed in the JavaScript code itself, as opposed to other web application components. These results indicate that JavaScript programmers and testers need tools that can help them reason about the DOM. Additionally, developers can use the error patterns we found to design more powerful static analysis tools for JavaScript. Client-side JavaScript is being widely used in popular web applications to improve functionality, increase responsiveness, and decrease load times. However, it is challenging to build reliable applications using JavaScript. This paper presents an empirical characterization of the error messages printed by JavaScript code in web applications, and attempts to understand their root causes. We find that JavaScript errors occur in production web applications, and that the errors fall into a small number of categories. We further find that both non-deterministic and deterministic errors occur in the applications, and that the speed of testing plays an important role in exposing errors. Finally, we study the correlations among the static and dynamic properties of the application and the frequency of errors in it in order to understand the root causes of the errors.