JavaScript short answer questions Since there are many questions, only some basic questions are listed below.
Answer: JavaScript is an interpreted scripting language.
Answer: Use the var keyword to define variables, for example: var a = 1;
Answer: Data types in JavaScript mainly include numeric, string, Boolean, undefined and null.
Answer: Use the typeof operator, for example: typeof a;
Answer: Use the parseInt() or parseFloat() function to convert the string into a numeric type.
Answer: Use the toString() method to convert the numeric value into a string.
Answer: Use the operator for string concatenation, for example: "Hello" "World";
Answer: The logical operators in JavaScript include logical AND (&&), logical OR (||) and logical NOT (!).
Answer: Use a for loop to traverse the array, for example: for(var i = 0; i < arr.length; i ) {}
Answer: Use a for-in loop to traverse object properties, for example: for(var prop in obj) {}
Answer: Events in JavaScript mainly include mouse events, keyboard events, form events, and form events.
Answer: Use the addEventListener() method to bind events, for example: element.addEventListener("click", function(){}).
Answer: Use the removeChild() method to delete nodes, such as parentElement.removeChild(childElement).
Answer: Use the XMLHttpRequest() constructor to create an XMLHttpRequest object. For example: var xmlhttp = new XMLHttpRequest().
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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