Linked Questions
89 questions linked to/from How do I check for an empty/undefined/null string in JavaScript?
3140
votes
47
answers
3.1m
views
Is there a standard function to check for null, undefined, or blank variables in JavaScript? [duplicate]
Is there a universal JavaScript function that checks that a variable has a value and ensures that it's not undefined or null? I've got this code, but I'm not sure if it covers all cases:
function ...
- 36k
130
votes
5
answers
609k
views
Javascript: How to check if a string is empty? [duplicate]
I know this is really basic, but I am new to javascript and can't find an answer anywhere.
How can I check if a string is empty?
- 241k
18
votes
1
answer
13k
views
JS how to check empty String and Space [duplicate]
Help me pls
if(value == ""){
// do anything
}
but I need to check space " " (2,3,... space is include) is the same way of empty String
ps. sorry in my English
-4
votes
3
answers
56k
views
How can I check if the input is empty in JavaScript? [duplicate]
I am trying to make a factorial calculator. How can I check if the input is empty or not? I tried 'null'. But it didn't work or I couldn't use it properly.
sorry for the stupid question. I am newbie ...
9
votes
0
answers
20k
views
Validating a non-empty String in Lo-Dash [duplicate]
[Use-case: portable Lo-Dash code]
I've been looking for an elegant Lo-Dash empty-string validator in our nodeJS projects for some time now, because _.isEmpty() only handles Arrays and Objects. So I ...
- 131
3
votes
2
answers
11k
views
How to check empty in variable in Google Apps Script [duplicate]
I have a variable that can be either empty, number or text. I like to find only empty one. But the following codes using .length returned null for 0 number, though it returned 1 for "0" ...
- 283
5
votes
1
answer
618
views
String check with if js shorthand [duplicate]
I have var names = []; and want push there some string only if it's not empty. Is there way make it with some shorthand method in js?)
That i have now.
if ("" != opportunityName)
{
names....
- 458
-1
votes
1
answer
508
views
If input has spaces only [duplicate]
Hi there everyone how can I detect if the user input has just empty spaces?
Detect this:
input = ' ';
input = ' ';
etc...
DO NOT detect this:
input 'hi there';
I just want to detect if ...
- 989
0
votes
1
answer
258
views
Checking the input if its empty [duplicate]
I am pretty new to jQuery so I have a problem with this.
I am trying to check if input is empty by jQuery. I have this script:
$('#submit').click(function(){
if($.trim($('#username').val()) == ...
- 55
-1
votes
1
answer
104
views
How to check if value contains at least one character, expect for space [duplicate]
I`m building messaging app and I need regex or some other way to validate message that user is about to send. Message must contain at least one character, expect for space.
const valid = *regex*
...
-5
votes
1
answer
90
views
How to shorten text in Javascript [duplicate]
I am trying to reduce the length of the text that I have requested from
the API with the 'slice' method. but it is throwing an error of
'Cannot read property 'slice' of undefined.
- 5
1
vote
0
answers
88
views
How do I get the console to print out the name, keeping in mind the name variable isn't constant? [duplicate]
I'm trying to create a ternary expression that decides what to do if the user enters a name or not. If the user enters a name — like 'Jane' — use string interpolation to log Hello, Jane! to the ...
- 13
0
votes
0
answers
18
views
Boolean conditionals with placeholder [duplicate]
super beginner here:
I having trouble figuring out how to correctly use this conditional statement for a placeholder. For some reason, it only executes one condition after clicking on submit (in this ...
- 35
5644
votes
47
answers
2.2m
views
Which equals operator (== vs ===) should be used in JavaScript comparisons?
I'm using JSLint to go through JavaScript, and it's returning many suggestions to replace == (two equals signs) with === (three equals signs) when doing things like comparing idSele_UNVEHtype.value....
- 57.4k
3889
votes
41
answers
4.4m
views
How do I test for an empty JavaScript object?
After an AJAX request, sometimes my application may return an empty object, like:
var a = {};
How can I check whether that's the case?
- 39.3k