Solution: We can display data in many ways in JavaScript.They are innerHTML, console.log(), window.alert(), document.write. document.getElementById(id) is a method used for accessing HTML element by JavaScript. Here id defines the HTML element.

Solution: For testing we used document.write() in JavaScript. If we use document.write() after HTML document, it will delete all existing HTML. This method can only be used for testing purposes.
 

Solution: By using debugger keyword execution of JavaScript stops, and is debugger function is defined it is called at the moment, break is the keyword used to terminate a loop or a switch, return is used for exit from a function, try…catch handle the errors.

Solution: Arrays in JavaScript are written in square brackets. The elements of array are separated by commas. Index of array items starts from 0. E.g. var fruits= [“apple”, “orange”, “banana”, “pine-apple”]; objects in JavaScript are written inside curly brackets.

Solution: typeof “null” in JavaScript is an object. Basically null indicates nothing like it is a thing that does not exist. It is like a bug in JavaScript that its typeof comes to be an object. For emptying an object we can set it to null.

Solution: While using slice(), substr() and substring() method we pass numbers as parameters respective to the string. E.g var tes= str.slice(-10). -10 is indicates negative position. It does not work in Internet Explorer or older versions.

Solution: For converting any string to an array we use split() method. E.g. var tr=”t,o,I,k,l”; tr.split(“,”); tr.split(“|”); tr.split(“ ”); charAt returns a character from the given index, charCodeAt() returns Unicode of character at the given index. toLowerCase() method converts input string into lower case string.

Solution: The numbers according to international IEEE 754 standard are stored as a double precision floating point. It stores the numbers in 64-bit format, stored in bits from 0 to 51, exponent in bits is from 52 to 62 and signs in a bit is 63.

Solution: The integers in JavaScript have accuracy up to 15 digits. E.g. var y=111111111111111; // value of y will be 111111111111111. For decimal the maximum number of decimals is 17.