How to verify that user entered empty string? in PHP

Question

I need to know how to verify that the user entered empty string in a sentence if in a string with multiple spaces in blank

Example

  "                         "

if user entered a emṕty string, the program must show an alert as this

echo "The username must not be empty";

PHP is server side, JavScript/jQuery is client side. You're mixing the two, it'd be easier to just do this in jQuery OR PHP depending on your needs — Andy Holmes, Jan 26 '15 at 16:46
if you want to stop or validate form submission, you can prevent it with js, like here http://stackoverflow.com/questions/8664486/javascript-to-stop-form-submission — Eugen, Jan 26 '15 at 16:49

score 8 · Accepted Answer · answered Jan 26 '15 at 16:44

8

Use trim to remove whitespace from a var...

$name = trim($_GET['name']);

if ($name == '') //empty

answered Jan 26 '15 at 16:44

fire

Out of interest, what's the difference between this and `!$name`? – Andy Holmes Jan 26 '15 at 16:48
1

@AndyHolmes with PHP being loosely typed; nothing really. `!$name` is equivalent to `$name == false` which is equivalent to `$name == ''` ... it would only make a difference with strict evaluation `===`; you do have to be a little careful though as `0 == false` but `'0' == true` ;) – CD001 Jan 26 '15 at 16:52

score 2 · Answer 2 · answered Jan 26 '15 at 16:49

2

Try this

if (strlen(trim($yourString)) == 0) {
    // Do something
}

If the length of the string is 0 after the spaces are trimmed/removed.

answered Jan 26 '15 at 16:49

KWILLIAMS

2 Answers2