FAQs
The null value represents the intentional absence of any object value. It is one of JavaScript's primitive values and is treated as falsy for boolean operations.
What does null mean in computer terms? ›
The value null means that no value exists. When used as a value, null is not a memory location. Only pointers hold memory locations. Without a null character, a string would not correctly terminate, which would cause problems.
What does null mean in JavaScript? ›
In JavaScript, null and undefined represent the absence of a value. null is an assignment value that represents no value or no object. It is often used to indicate that a variable has no value or that an object does not exist.
Are MDN docs good? ›
MDN Web Docs is very good for both types — the area you are currently in is great for learning techniques and concepts, and we also have several giant reference sections allowing you to look up any syntax you can't remember.
What is the null code? ›
In all modern character sets, the null character has a code point value of zero. In most encodings, this is translated to a single code unit with a zero value. For instance, in UTF-8 it is a single zero byte. However, in Modified UTF-8 the null character is encoded as two bytes: 0xC0,0x80.
What is a null value? ›
A NULL value is a special marker used in SQL to indicate that a data value does not exist in the database. In other words, it is just a placeholder to denote values that are missing or that we do not know. NULL can be confusing and cumbersome at first. But it is imperative for any analyst to know how to handle them.
What is NULL website? ›
About us. null - The Open Security Community The community is for cyber security professionals & enthusiasts. Connect with like-minded people and collaborate!
What is NULL used for? ›
A NULL value is used to represent a missing value, but it usually has one of three different interpretations: The value unknown (value exists but is not known) Value not available (exists but is purposely withheld) Attribute not applicable (undefined for this tuple)
What is an example of NULL in programming? ›
In JavaScript, null is a special value that represents an empty or unknown value. For example, let number = null; The code above suggests that the number variable is empty at the moment and may have a value later.
What are examples of null in JavaScript? ›
JavaScript Demo: Expressions - Nullish coalescing operator
- const foo = null ?? 'default string';
- console. log(foo);
- const baz = 0 ?? 42;
- console. log(baz);
We'll discuss why it's not a good practice, and suggest better alternatives to use instead. When a variable or object reference is set to null , it means it does not point to any valid object or value. This can cause runtime errors such as NullReferenceExceptions, and is a common source of bugs in software development.
How do you find null in JavaScript? ›
How to check for null values in JavaScript ?
- By equality Operator (===)
- By Object.is() function.
- By the typeof Operator.
- Using Lodash _.isNull() Method.
I think for really small tasks in HTML and CSS then w3schools is fine. But if you are looking for more substantial and trusted web development content than MDN is better.
Who owns MDN? ›
Since its beginning in 2005, MDN Web Docs has been a project hosted and provided by Mozilla. Mozilla covers the cost of infrastructure, development and maintenance of the MDN platform, including a team of engineers and its own team of dedicated writers.
Who writes MDN Web Docs? ›
MDN Web Docs content is maintained by Mozilla, Google employees, and volunteers (community of developers and technical writers).
What is my null value? ›
What is a NULL Value? A field with a NULL value is a field with no value. If a field in a table is optional, it is possible to insert a new record or update a record without adding a value to this field. Then, the field will be saved with a NULL value.
What is the null value in Java? ›
In Java, null is a keyword much like the other keywords public, static or final. It is just a value that shows that the object is referring to nothing. The invention of the word “null” originated to denote the absence of something. For example, the absence of the user, a resource, or anything.
Why is NULL == 0 false? ›
Comparisons convert null to a number, treating it as 0 . That's why (3) null >= 0 is true and (1) null > 0 is false. On the other hand, the equality check == for undefined and null is defined such that, without any conversions, they equal each other and don't equal anything else. That's why (2) null == 0 is false.
Why is NULL == undefined true? ›
undefined is a primitive type of a variable which evaluates falsy, has a typeof() of undefined, and represents a variable that is declared but missing an initial value. null == undefined evaluates as true because they are loosely equal. null === undefined evaluates as false because they are not, in fact, equal.
