A brief analysis of the difference between JavaScript and Java_Basic knowledge

The following is a comparison of the similarities and differences between the two languages:
1. Object-based and object-oriented
Java is a true object-oriented language, even when developing simple programs. Objects must be designed. JavaScript is a scripting language that can be used to create complex software that is network-independent and interacts with users. It is an Object Based and Event Driver programming language. Therefore it itself provides a very rich set of internal objects for designers to use.
2. Interpretation and compilation
The two languages ​​are executed differently in their browsers. Java source code must be compiled before being passed to the client for execution. Therefore, the client must have an emulator or interpreter on the corresponding platform. It can compile the code independently of a specific platform through the compiler or interpreter. of bondage.
JavaScript is an interpreted programming language. Its source code does not need to be compiled before being sent to the client for execution. Instead, character codes in text format are sent to the client for interpretation and execution by the browser.
3. Strong variables and weak variables
The variables adopted by the two languages ​​are different. Java uses strong type variable checking, that is, all variables must be declared before compilation. For example:

Copy code The code is as follows:

Integer x;
String y;
x=1234;
x=4321;

Among them, X=1234 means it is an integer, and Y=4321 means it is a string. Variable declaration in JavaScript adopts its weak type. That is, variables do not need to be declared before use, but the interpreter checks their data type at runtime, such as:

Copy code The code is as follows:

x=1234;
y="4321";

The former indicates that x is a numeric variable, while the latter indicates that y is a character type variable.
4. The code format is different
Java is a format that has nothing to do with HTML. It must be loaded like foreign media is quoted in HTML. Its code is saved in the form of byte code. in a separate document. JavaScript code is a text character format that can be directly embedded in HTML documents and can be loaded dynamically. Writing HTML documents is as easy as editing text files.
5. The embedding methods are different
In HTML documents, the two programming languages ​​have different logos. JavaScript uses to identify, while Java uses to identify.
6. Static binding and dynamic binding
Java uses static binding, that is, Java object references must be made at compile time so that the compiler can implement strong type checking. JavaScript uses dynamic binding, that is, JavaScript object references are checked at runtime. Without compilation, object reference checking cannot be achieved.