The only goal of the human-computer interaction (HCI) is to meet user needs and expectations as much as possible, and then to improve the usability of software systems[7; 8]. Usability methods have from the beginning of times, that is to say the early 80’s, always included users to varying degrees. The usability is an important indicator of quality of the interactive IT product or system. Nielsen has pointed out that the usability is effective, easy to learn, efficient, easy to remember, the fewer mistakes and satisfaction for product users . The international standard ISO 9241-11 defines usability as follows: effectiveness, efficiency and satisfaction what are qualities of products in a particular environment for a specific user for specific purposes.
The concept of usability engineering appeared, as people have an emphasis on the quality of product since the 80s of last century, and then has correspondingly formed a popular area in academia and industry. Usability engineering is an engineering methodology for the IT product and user interface development, throughout the product life cycle stages. Its core is UCD methodology, stressing from the user’s point of view to design and development .
B. Web Usability
Design In Internet time, Web-based applications are to interact with users through the Web user interface in Internet. Web interface is a specific human-machine interface based on Internet technology, and Web is a special interactive system in the Internet environment. Web usability engineering is that principles and techniques of the usability engineering are applied to Web design, so that Web designers construct usercentric website rather than the technology-centric website, who should focus on its user, rather than the computer’s input and output.
That is, Web design is changed from technology-driven to user-driven. Web interface design is developed from the graphical user interface (GUI) design about software based on screen, and the design to following the same design fundamentals of other. That is Web design must directly face “users with the specific needs”, and must ensure that users are pleasant to successfully complete tasks with Web. Web design usually adapts a design – evaluation iterative design process to improve its usability. Web usability design includes the following three main elements: research users, Web design, and usability evaluation.