This article describes a novel technique for crawling Ajax-based applications through automatic dynamic analysis of user-interface-state changes in Web browsers. At the same time, such techniques-collectively known as Ajax-shatter the concept of webpages with unique URLs, on which traditional Web crawlers are based. Using JavaScript and dynamic DOM manipulation on the client side of Web applications is becoming a widespread approach for achieving rich interactivity and responsiveness in modern Web applications. Based on these criteria we plot the evolution of web crawlers. We introduce criteria to evaluate the relative performance and objective of web crawlers. What follows is a brief history of different techniques and algorithms used from the early days of crawling up to the recent days. Additionally, capturing the model of a modern web application and extracting data from it automatically is another open question. Performing an exhaustive crawl is a challenging question. Different solutions have been proposed to reduce the time and cost of crawling. Throughout the history of web crawling many researchers and industrial groups addressed different issues and challenges that web crawlers face. Quick expansion of the web, and the complexity added to web applications have made the process of crawling a very challenging one. In addition to collecting statistics about the web and indexing the applications for search engines, modern crawlers can be used to perform accessibility and vulnerability checks on the application. Early web crawlers collected statistics about the web. Web crawlers have a long and interesting history. In addition, we provide some future directions for research on crawling RIAs. This paper surveys the research on addressing the problem of crawling RIAs and provides some experimental results to compare existing crawling strategies. Traditional crawlers are not able to handle these newer technologies. Without crawling, RIAs cannot be indexed nor tested automatically. One important challenge is the difficulty of automatically crawling these new applications. However, at the same time, such techniques also introduced new challenges. These applications, often called Rich Internet Applications (RIAs), changed the web applications in two ways: (1) dynamic manipulation of client-side state and (2) asynchronous communication with the server. With the emergence of richer and more advanced technologies such as AJAX, web applications have become more interactive, responsive and user friendly. Web applications have come a long way, both in terms of adoption to provide information and services, and in terms of the technologies to develop them. In an empirical study, this method found failures in 16 of 26 real-world production pages studied, detecting 33 distinct failures in total. This paper presents an automated failure detection technique that checks the consistency of a responsive page’s layout across a range of viewport widths, obviating the need for an explicit oracle. A central problem is the difficulty in providing an automated “oracle” to validate RWD layouts against, meaning that checking for failures is largely a manual process in practice, which results in layout failures in many live responsive web sites. However, a current lack of automated support means that presentation failures may go undetected in a page’s layout when rendered for different viewport sizes. When developers adopt responsive web design (RWD) techniques, web pages modify their appearance to accommodate a device’s display constraints. As the number and variety of devices being used to access the World Wide Web grows exponentially, ensuring the correct presentation of a web page, regardless of the device used to browse it, is an important and challenging task.
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