JavaScript Question Answers - 121-140

121. Why it is not advised to use innerHTML in JavaScript?

- It replaces all content instead of appending.
- It re-parses and rebuilds the DOM, which is slower.
- It can insert invalid or unsafe HTML.
- It removes existing event handlers.

122. Which method returns the inner width of a window's content area

window.innerWidth

123. What does this statement declare: var myArray = [ ];

It declares a three-dimensional array with one element, which itself contains an empty array inside another array.

124. What is this keyword?

this refers to the current execution context (the object that owns the function being executed).

125. What is negative infinity?

Number.NEGATIVE_INFINITY is a special numeric value returned when a negative number is divided by zero.

126. In JavaScript how to display a string in italic

document.write("Hello".italics());

127. What is JavaScript

JavaScript is a lightweight, interpreted, object-based scripting language used to make web pages interactive and dynamic.

128. Which method joins all elements of an array into a string

Array.join(separator)

129. Which method searches the array for an element, starting at the end, and returns its position

Array.lastIndexOf(element)

130. Which method returns the position of the last found occurrence of a specified value in a string

String.lastIndexOf(value)

131. Which method returns the number of <iframe> elements in the current window

document.getElementsByTagName("iframe").length

132. In JavaScript how to display a string as a hyperlink

document.write("Click".link("https://example.com"));

133. Which property returns the natural logarithm of 10 (approx. 2.302)

Math.LN10

134. Which property returns the natural logarithm of 2 (approx. 0.693)

Math.LN2

135. Which method Compares two strings in the current locale

str1.localeCompare(str2)

136. Which method returns the Location object for the window

window.location

137. Which method returns the natural logarithm (base E) of x

Math.log(x)

138. Which property returns the base-10 logarithm of E (approx. 0.434)

Math.LOG10E

139. Which property returns the base-2 logarithm of E (approx. 1.442)

Math.LOG2E

140. Which method searches a string for a match against a regular expression, and returns the matches

str.match(regex)