The questions in this JavaScript quiz are on the topics covered in the JavaScript Intermediate section of the site. The table below lists the
lessons, a description of the lesson content and the the quiz question number range.
Lesson Summary
Click on a lesson in the table to go to that lesson for a refresher on the topics for that lesson.
JavaScript Quiz
The quiz below tests your knowledge of the material learnt in the JavaScript Intermediate section of the site.
Question 1 : What happens when we try to create an array without passing any arguments?
- When no arguments are passed an empty array is created.
Question 2 : When we create an array with one argument and the argument is not a number what happens?
- When we create an array with one argument and the argument is not a number an array is created with a length of 1, with the argument as the first elements value.
Question 3 : On array creation when one argument is passed and it is a number between 0 and 4,294,967,295 an array is created with that length. What happens when a number outside these parameters is passed?
- When one argument is passed and it is a number outside the parameter range 0 and 4,294,967,295 a <code>RangeError</code> exception is thrown.
Question 4 : When creating an array using array literal syntax what symbols are used?
- When creating an array using array literal syntax we use the <code>[]</code> symbols.
Question 5 : Date creation using the milliseconds parameter starts from which date.?
- Date creation using the milliseconds parameter starts from 1 January 1970 00:00:00 UTC.
Question 6 : Date creation using the milliseconds parameter can use negative as well as positive values?
- Date creation using the milliseconds parameter can use negative as well as positive values.
Question 7 : Is the following code a valid way of creating a Date object?
var aDate = new Date(Jan 1, 2000);
- Yes we can parse a date when creating a Date instance.
Question 8 : We must always use an else with an if statement?
- We can have an <code>if</code> without an <code>else</code>.
Question 9 : What is output from the following conditional statement?
var aVariable = false;
if (aVariable = true) {
alert('true');
} else {
alert('false');
}
- We are actually assigning <code>true</code> in the <code>if</code> statement. To compare values we need to use <code>==</code>
Question 10 : We can have an if statement with mutiple if....else statements within it?
- An <code>if</code> statement can contain mutiple if....else statements within it.
Question 11 : Which of these loop statements will always execute at least once?
- The <code>do....while</code> statement will always execute at least once.
Question 12 : Which statement allows us to exit a loop?
- The <code>break</code> statement allows us to exit a loop.
Question 13 : Which statement allows us to carry on from the expression part of a loop?
- The <code>continue</code> statement allows us to continue from the expression part of the loop.
Question 14 : What would happen if we tried to run the following for loop code?
for (;;) {
alert('In loop');
}
- The <code>for</code> loop code loops endlessly.
Question 15 : How many times will the following for loop execute?
for (var i=0; i<3; i++) {
alert('The i variable is = ' + i);
}
- The <code>for</code> loop code executes 3 times.
Question 16 : We can use break statements within our for loops?
- Yes we can use The <code>break</code> statements within our for loops.
Question 17 : What is generally returned from functions when a numerical value can't be derived or is unobtainable?
- <code>NaN</code> is generally returned from functions when a numerical value can't be derived or is unobtainable.
Question 18 : What is alerted from the following code?
nanResult = NaN == NaN;
alert(nanResult);
- The Nan global property is also unique in JavaScript in the fact that you cannot rely on the equality (==) and strict equality (===) comparison operators to find out whether a value is Nan or not.
Question 19 : What is the parseFloat() function used for?
- The <code>parseFloat()</code> function is used to convert a string to a decimal.
Question 20 : Care should be taken when using the IsNaN() function as results can be unexpected.?
- Parsing a string that cannot be converted to a numeric gives a double positive and makes <code>isNaN()</code> unreliable in this situation.
Question 21 : What does the acornym JSON stand for?
- <code>JSON</code> is an acornym for JavaScript Object Notation.
Question 22 : When using the JSON style of coding what symbols do we use to mark object boundaries?
- The <code>JSON</code> style of coding uses matching braces to mark object boundaries.
Question 23 : One advantage of using JSON is that code is more compact, what's another advantage?
- The advantages of using JSON is that code is more compact and visually more informative of object structure.
Question 24 : Which is the least efficient way to create a function?
- Using the <code>Function</code> constructor to create a function is the least efficient way to create functions as they are parsed on function creation as opposed to being parsed with the rest of the JavaScript code..
Question 25 : What method can we use for function chaining?
- We can use both the <code>apply()</code> and <code>call()</code> methods for function chaining.
Question 26 : What statement is used to pass a value back from a function?
- The <code>return</code> statement is used to pass a value back from a function.
Question 27 : What symbol do we use to escape special characters when using the RegExp constructor?
- We use the <code>\</code> (backslash symbol) to escape special characters when using the <code>RegExp</code> constructor.
Question 28 : We have a choice of 3 flags to use with regualr expressions and all are mutually exclusive?
- Flags can be used individually or in combination and are applied to the characters we are searching with the regular expression pattern.
.
Question 29 : Is the following code a valid way to create a regular expression?
var newRegExp = /\d/;
- The code is an example of creating a regular expression using lieral format and is perfectly valid.
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What's Next?
In the next quiz we test our knowledge of the topics covered in the JavaScript Advanced section of the site .
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