What short answer questions are there in javascript?

JavaScript short answer questions Since there are many questions, only some basic questions are listed below.

1. What type of language is JavaScript?

Answer: JavaScript is an interpreted scripting language.

2. How to define a JavaScript variable?

Answer: Use the var keyword to define variables, for example: var a = 1;

3. What are the data types in JavaScript?

Answer: Data types in JavaScript mainly include numeric, string, Boolean, undefined and null.

4. How to determine the data type of a variable?

Answer: Use the typeof operator, for example: typeof a;

5. How to convert a string into a numeric type?

Answer: Use the parseInt() or parseFloat() function to convert the string into a numeric type.

6. How to convert numeric value to string?

Answer: Use the toString() method to convert the numeric value into a string.

7. How to perform string concatenation?

Answer: Use the operator for string concatenation, for example: "Hello" "World";

8. What are the logical operators in JavaScript?

Answer: The logical operators in JavaScript include logical AND (&&), logical OR (||) and logical NOT (!).

9. How to traverse an array?

Answer: Use a for loop to traverse the array, for example: for(var i = 0; i < arr.length; i ) {}

10. How to traverse an object properties in?

Answer: Use a for-in loop to traverse object properties, for example: for(var prop in obj) {}

11. What are the events in JavaScript?

Answer: Events in JavaScript mainly include mouse events, keyboard events, form events, and form events.

12. How to bind an event?

Answer: Use the addEventListener() method to bind events, for example: element.addEventListener("click", function(){}).

13. How to delete a node?

Answer: Use the removeChild() method to delete nodes, such as parentElement.removeChild(childElement).

14. How to create an XMLHttpRequest object?

Answer: Use the XMLHttpRequest() constructor to create an XMLHttpRequest object. For example: var xmlhttp = new XMLHttpRequest().

15. How to send an Ajax request?

Answer: Use the open() and send() methods of the XMLHttpRequest object to send an Ajax request. For example: xmlhttp.open(“GET”, “url”, true); Advanced topics that require further study and mastery.

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