JavaScript reserved words and their meanings

Javascript is a widely used programming language, and its reserved words are keywords with special meanings in this language. In Javascript, there are some words that cannot be used as variable or function names because they have been defined as reserved words.

The following are common reserved words in Javascript and their meanings:

1. break - used to break out of loop statements, usually with for , while, do while and other loop statements are used together.
2. case - Used to select a branch in the switch statement.
3. catch - Used to catch exceptions and execute the corresponding code block when an exception occurs.
4. continue - Used to skip the current iteration in a loop and continue with the next iteration.
5. debugger - Used to set program break points to debug code.
6. default - A default option in the switch statement.
7. delete - Used to delete a property in an object or an element in an array.
8. do - Used to create a do while loop.
9. else - If the if condition is not met, execute the code in the else code block.
10. false - Boolean value indicating false.
11. finally - Always executed after a try code block has finished executing.
12. for - Used to create a for loop.
13. function - used to define a function.
14. if - Used to specify a condition and execute the corresponding code block based on the condition.
15. in - Used to check whether a certain property exists in an object.
16. instanceof - Used to check whether an object is an instance of a specific class.
17. new - Used to create an object.
18. null - represents an empty object.
19. return - Used to return the result of a function call.
20. switch - Used to select between multiple options.
21. this - represents the current object.
22. throw - used to throw a new error.
23. true - Boolean value, indicating true.
24. try - Creates a block of code where an exception may occur.
25. typeof - used to check data type.
26. undefined - Indicates an undefined value.
27. var - used to declare a variable.
28. void - Used to specify that the return value of an expression is undefined.
29. while - Used to create a while loop.
30. with - Used to make an object part of the current running environment.

When programming in Javascript, we need to pay attention to the meaning of these reserved words to avoid unnecessary errors in the program. At the same time, we also need to avoid using these reserved words as variable or function names, so as not to conflict with the built-in functions of Javascript and affect the normal operation of the program.

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