responseText contains extra whitespace characters (new lines, line feeds), how to prevent and remove them?

Jamex picture Jamex · Aug 26, 2011 · Viewed 8k times · Source

I have an ajax script that calls a php file.

The php file echos "yes" or "no", I want to use the strings to do logical comparisons.

In the javascript, I want to compare the string in the responseText to see if it is == to "yes" (or "no"). But the comparison fails.

So I do the alert responseText, and it does show "yes" (or "no") as the string. But I read on here that the responseText might contain hidden whitespace characters, so I did the string length of responseText and it shows that the string length is 4 characters longer than what it should be. So I escaped the responseText alert(escape(responseText)) and it shows that I have %0A and %0D (newlines and line feeds) hidden at the end of the responseText string.

I read that these characters are added on by php, but I also read that the extra characters are different among different php versions/servers.

How to prevent these extra whitespaces without using regex, since regex might remove intentional whitespaces?

Please don't suggest using jquery or mootools as answers.

TIA

Answer

Arnaud Le Blanc picture Arnaud Le Blanc · Aug 26, 2011

I read that these characters are added on by php, but I also read that the extra characters are different among different php versions/servers.

That's wrong. That's simple to verify: create a test.php file, write this and only this: <?php echo "test"; (without ?>) into it and execute it. There will be no whitespace.

These whitespaces most probably come from your scripts. A common error is to leave some trailing newlines after a closing php tags (?>), which results in a new line being printed.

Verify that all files included before or after you do echo "yes"; don't echo anything and don't have a trailing newline after a ?>.

The easiest way to avoid this problem is do not use php close tags at end of files (they are not mandatory).