Understanding level of JavaScript

The popularity and Application of JavaScript is far higher than that of Java. Like CSS and HTML, JavaScript is a required course for all web developers.

Javascript is a weakness in the eyes of many people. Its application value is limited to client data verification. Javascript is an indispensable part of the Web field, and developers have different levels of understanding of it.

1. Data verification tools. This is the scenario where Javascript is most widely used and the first step for most web programmers to create an impression of JavaScript. This step has already been passed by too many web programmers. Therefore, for new web developers, they just need to download some JS programs developed by others for verification on the Internet and directly call them. Data verification is just the first step for JavaScript to be used as a language.

2. Oo. With some web development experience, programmers often need to meet some special requirements of users on the client. The simplest case is to implement the option box association between provinces and cities-maybe this is also the experience that most web programmers can share. It is not difficult to achieve this, but in the implementation process, the programmer needs to operate select in the form of an object to generate a new option object. Although some JavaScript object-oriented features may already have a vague concept in data verification, when you are deeply aware of the Javascript oo features, your understanding of it has reached a level.

3. Dom parsing. I believe that most web programmers have gone through the second stage and have more or less used methods such as innerhtml and innertext to change the content of the current page area. The getelementbyxx method should also be familiar. After this process, the new problem you encounter during development is to find the desired location during document traversal and modify the content of this location. Innerhtml can be combined with getelementbyxx to solve some of these problems. No document ID is defined, or the content to be processed is scattered in each label. simply relying on this method is not that easy to solve the problem. Understanding how to parse the DOM using JavaScript is also the only way to process page features using JavaScript. In Ajax applications, the DOM parsing capability of JavaScript is very important. Tools for viewing real-time Page code are already essential for Web developers at this stage.

4. ECMA. As a standard in the Web development field, ECMA is just the core of JavaScript scripts. When web developers constantly solve JavaScript browser compatibility problems, they will be impulsive to understand this standard. With reference to the standard, programmers systematically sort out their understanding of JavaScript at this stage. It can be said responsibly that web programmers at this stage have been able to solve most JavaScript problems.

5. Special requirements are handled. In the fifth stage, Web developers often need to understand the new JavaScript Application Methods because of specific system requirements. For example, JavaScript WebService call method and JavaScript Regular Expression application. This requirement is not strong, but it does exist, so some programmers need to take this step. In the fifth stage, web programmers and in the fourth stage do not have the ability to distinguish between them. What is different is their experience in solving practical problems.

The above is a little superficial understanding of the Javascript learning stage, but it is basically my own deep understanding.