isnull javascript – JavaScript isNull | How to Check for null?

0
()

isnull javascript – How to Check for null or Empty String in JavaScript?

isnull javascript To check for null SPECIFICALLY you would use this: if (result === null). also you can cehck variable are Null, Empty String, Undefined, False, Zero and NaN Test.

isnull javascript – How to Check for null in JavaScript?

if(!pass || !cpass || !email || !cemail || !user){

return results == null ? 0 : (results[1] || 0);

Null Test:

if (result === null)

- result = ""; (false) typeof result = string

- result = null; (true) typeof result = object

- result = undefined; (false) typeof result = undefined

- result = false; (false) typeof result = boolean

- result = 0; (false) typeof result = number

- result = NaN; (false) typeof result = number

Empty String Test:

if (result === '')

- result = ''; (true) typeof result = string

- result = null; (false) typeof result = object

- result = undefined; (false) typeof result = undefined

- result = false; (false) typeof result = boolean

- result = 0; (false) typeof result = number

- result = NaN; (false) typeof result = number

Undefined Test:

if (typeof result == "undefined")

-- or --

if (result === undefined)

- result = ''; (false) typeof result = string

- result = null; (false) typeof result = object

- result = undefined; (true) typeof result = undefined

- result = false; (false) typeof result = boolean

- result = 0; (false) typeof result = number

- result = NaN; (false) typeof result = number

Don’t Miss : Check If Object Is Empty In VueJS

Read Also:  Bootstrap Toggle switch Update Database field using Ajax

False Test:

if (result === false)

- result = ''; (false) typeof result = string

- result = null; (false) typeof result = object

- result = undefined; (false) typeof result = undefined

- result = false; (true) typeof result = boolean

- result = 0; (false) typeof result = number

- result = NaN; (false) typeof result = number

Zero Test:

if (result === 0)

- result = ''; (false) typeof result = string

- result = null; (false) typeof result = object

- result = undefined; (false) typeof result = undefined

- result = false; (false) typeof result = boolean

- result = 0; (true) typeof result = number

- result = NaN; (false) typeof result = number

NaN Test:

if (typeof result == 'number' && !parseFloat(result) && result !== 0)

-- or --

if (isNaN(result))

- result = ''; (false) typeof result = string

- result = null; (false) typeof result = object

- result = undefined; (false) typeof result = undefined

- result = false; (false) typeof result = boolean

- result = 0; (false) typeof result = number

- result = NaN; (true) typeof result = number

Download

I hope you get an idea about isnull javascript.
I would like to have feedback on my infinityknow.com.
Your valuable feedback, question, or comments about this article are always welcome.
If you enjoyed and liked this post, don’t forget to share.

Read Also:  Compare two dates using JavaScript

How useful was this post?

Click on a star to rate it!

Free Live Chat for Any Issue