Top 7 Most Common JavaScript Mistakes

By Hardik Savani September 5, 2020 Category : Guest Post

Many of today’s web applications are possible because of JavaScript. Developers from all over the world have benefited from the increasing number of libraries in this programming language. Currently, JavaScript is used to develop single-page applications as well as some server platforms. The possibilities are endless and include graphics and very attractive animations.

The best websites are created using JavaScript. Thus, whether you are already building websites or just improving existing ones, JavaScript is the way to go. No wonder many students devote many efforts to learning and mastering JavaScript. It is a skill that can open many doors in the web development industry.

Hence, mastering JavaScript is a must for any web developer. Different online services like can help with JavaScript homework assignments for students to achieve good proficiency in this language in a shorter time. This skill is indispensable to build modern and functional websites. Thus, do not hesitate to invest all the possible resources to learn JavaScript well.

For an experienced programmer or developer, JavaScript seems very easy to learn. In a sense it is. Implementing some web functions can be relatively easy for an experienced web developer; even if he or she has never used JavaScript before. However, this language can be leveraged to build very sophisticated functionality into web pages. This is why mastering JavaScript takes some time.

And many programmers that already have an intermediate to advance level in JavaScript, still make some mistakes while programming. To help you to avoid these mistakes, a compilation of the top 7 most common JavaScript mistakes is presented below. Do not be discouraged if you find out that you have been making one or several of these mistakes. Practice makes perfect. Thus, read on.

Everybody Makes Mistakes

While JavaScript may be an easy-to-learn language, mastering it takes time and patience just like with any other programming language. Beginners often make mistakes. But so do intermediate and advanced programmers. Thus, see below the list of the most common JavaScript mistakes:

  • Most programmers forget that the names of variables and functions in JavaScript are case sensitive. Thus, even a single letter that is not written with the proper case can cause an error;

  • Programmers often confuse the β€œ= =” and β€œ=” operators, especially when they need to do a comparison. Let us see the difference between them. The β€œ= =” operator performs a comparison, whereas the β€œ=” operator is used to assign a value to a variable. If you use one instead of the other, an error may appear in other programming languages. However, in JavaScript, any use of these operators will be evaluated. Thus, the result may be something completely unexpected, which makes the identification of the problem more difficult;

  • Many programmers forget using the reference identifies β€œthis.” Whenever you define a function in an object, this must be identified with the keyword β€œthis;”

  • Likewise, programmers often confuse between undefined and null. These two keywords have different meanings in JavaScript. The first one, undefined, refers to a variable that has been declared but to which no value has been assigned. On the other hand, null is a value that can be assigned to a variable to indicate that the variable has no value;

  • Both addition and string concatenation are performed using the β€œ+” operator in JavaScript. Thus, one must be very careful with its use to avoid an unexpected result. When you add a number as a number, the result will be an arithmetic addition. However, if you add a number as a string, the result will be the concatenation of characters. Beginners often make this mistake, although an oversight by an expert can result in this mistake;

  • You must know that the JavaScript code is executed following the order in the source. Thus, when you program in JavaScript, you must be sure that the code you reference is loaded first. There are different ways to avoid any mistake caused by this issue;

  • Many programmers avoid using semicolons to make the program run faster. However, semicolons help to keep the code readable. It has been demonstrated that the use of semicolons does not affect the execution speed. Thus, you should not make this common mistake.

  • These are some of the most common JavaScript mistakes. Of course, there are many more mistakes that programmers usually make. However, with practice, you will eventually become a proficient JavaScript programmer.

    Just pay attention to the way JavaScript works. Also, pay attention to how it does not work. As said, this knowledge comes after many hours of programming. So, do not give up. Practice whenever you have the opportunity to do it. Read as many JavaScript books as you can. There are many tutorials online that can help you to understand more deeply the JavaScript programming paradigms.

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