This error occurs when you read a property or call a method on a null object . That’s because the DOM API returns null for object references that are blank. An object is expected somewhere and wasn’t provided.
Is null == undefined?
null is an assigned value. It means nothing. undefined means a variable has been declared but not defined yet.
How do I fix NULL error?
The #NULL! error is quite rare in Excel, and is usually the result of a typo where a space character is used instead of a comma (,) or colon (:) between two cell references. This error may seem baffling to the average user, but in most cases replacing the space with a comma or colon will fix the problem.
How do I get a NULL error?
If you get this error because you’ve used a space character between ranges that don’t intersect, change the references so that ranges do intersect. For example, in the formula =CELL(“address”,(A1:A5 C1:C3)), the ranges A1:A5 and C1:C3 don’t intersect, and the formula returns the #NULL! error.
Is null an object Java?
No it’s not, and for those who wonder why such a question, there are languages where null is indeed an object like any, for example Ruby. In Scala, which is very meticulous about types, there is a type Null (a trait, actually) having a single instance null .
Instead, the problem can usually be resolved in one of two ways.
- Load the Libraries in Proper Order. Arguably, the most popular reason for seeing a ReferenceError has to do with the fact that our script is referencing a variable that has yet to be defined. …
- Leverage Undefined Values.
Only use null if you explicitly want to denote the value of a variable as having “no value”. As @com2gz states: null is used to define something programmatically empty. undefined is meant to say that the reference is not existing. A null value has a defined reference to “nothing”.
The isNaN() function determines whether a value is an illegal number (Not-a-Number). This function returns true if the value equates to NaN. Otherwise it returns false. This function is different from the Number specific Number.
Is NULL better than undefined?
null is a special value meaning “no value”. null is a special object because typeof null returns ‘object’. On the other hand, undefined means that the variable has not been declared, or has not been given a value.
Should I return NULL or undefined?
Undefined typically refers to something which has not yet been assigned a value (yet). Null refers to something which definitively has no value. In that case, I would recommend returning a null. Note that a function with no specified return value implicitly returns undefined.
Why is NULL == undefined true?
The == comparison operator doesn’t check the types. null and undefined both return false . That’s why your code is actually checking if false is equal to false .