CODEWITHSUNDEEP
javascript
Aero Wang
Aero Wang

Reputation: 9267

Javascript disallow space only in input area

I tried using following method to ban users from leaving only space in the input area with no luck:

method one:

var formSub  = $('#formsub').val();

if (formSub == null || formSub == "") {
  return false;
}

method two:

if (formSub.trim() == "" || formSub.trim() == " ") {
  return false;
}

method three: 

if ($.trim(formSub) == "" || $.trim(formSub) == " ") {
  return false;
}

Any thought? :)

Upvotes: 1

Views: 66

Answers (4)

Piotr Dajlido
Piotr Dajlido

Reputation: 2030

Haha! This is a good one you actually walk around the solution all along.

So here for example, you actually already trimmed all the spaces by using .trim()

if (formSub.trim() == "" || formSub.trim() == " ") {
  return false;
}

Correct would be just,

if (formSub == " ") {
  return false;
}

This will be the most useful, it passes if someone actually wrote something different from spaces, or other invisible characters ;) Google "Javascript Regex for more info"

if (/\S/.test(formSub)) {
   // String is not empty
}
else{
  // String is empty and not usefull
}

Cheers ;) ! +1 Appreciated

Upvotes: 0

user663031
user663031

Reputation:

Use a simple regexp:

/\S/.test(formSub)

where \S refers to any non-white space character.

This removes the dependency on trim (not found in IE<=8) and/or jQuery.

Upvotes: 2

James Wayne
James Wayne

Reputation: 1912

It should be formSub == null || formSub.trim() === "".

=== and == isn't exactly the same. == "" can means true, and any string is "true".

Upvotes: 1

k0pernikus
k0pernikus

Reputation: 66817

Try:

if (formValue.length === 0 || !formValue.trim()) {
    return false;
}

Upvotes: 0

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