How can I determine if a string only contains spaces, using javascript?

Question

How can I determine if an input string only contains spaces, using javascript?

http://stackoverflow.com/questions/3532053/regular-expression-for-only-characters-a-z-a-z Just use search. — ayk, May 10 '12 at 05:52

score 22 · Accepted Answer · edited Jul 25 '16 at 20:29

22

Another good post for : Faster JavaScript Trim

You just need to apply trim function and check the length of the string. If the length after trimming is 0 - then the string contains only spaces.

var str = "data abc";
if((jQuery.trim( str )).length==0)
  alert("only spaces");
else 
  alert("contains other characters");

edited Jul 25 '16 at 20:29

Daniel

6,194
7
33
59

answered May 10 '12 at 05:52

Pranay Rana

175,020
35
237
263

1

Or just `!str.trim()` – Oriol Mar 04 '16 at 18:52

score 9 · Answer 2 · answered May 10 '12 at 05:52

9

if (!input.match(/^\s*$/)) {
    //your turn...
}

answered May 10 '12 at 05:52

Chuck Norris

15,207
15
92
123

This assumes that `input` is the value, not the input element. – Joseph May 10 '12 at 05:56
Yeah, like `var input="dfdfd"`, I guess, getting input value from real input not a big problem. – Chuck Norris May 10 '12 at 05:57
I prefer this solution to .trim(), because you're looking for a specific pattern of characters, and that's precisely and explicitly what a regex describes. It would take a reader a little longer to understand your clever trick with trim. – Chris Mar 04 '16 at 18:55

score 2 · Answer 3 · answered May 10 '12 at 05:59

2

Alternatively, you can do a test() which returns a boolean instead of an array

//assuming input is the string to test
if(/^\s*$/.test(input)){
    //has spaces
}

answered May 10 '12 at 05:59

Joseph

117,725
30
181
234

score 0 · Answer 4 · answered May 10 '12 at 05:54

0

if(!input.match(/^([\s\t\r\n]*)$/)) {
    blah.blah();
}

answered May 10 '12 at 05:54

Derek 朕會功夫

92,235
44
185
247

score 0 · Answer 5 · answered Mar 04 '16 at 18:48

The fastest solution is using the regex prototype function test() and looking for any character that is not a space or a line break \S :

if (/\S/.test(str))
{
    // found something other than a space or a line break
}

In case that you have a super long string, it can make a significant difference.

How can I determine if a string only contains spaces, using javascript?

5 Answers5

Linked