Single quotes turning url into twins? - php

Question

Just noticed that when using single quotes to echo a basic link in php, the url repeats itself.
<?php
echo 'Link URL - Single Quotes<br />';
?>
The above code outputs the link as:
http://example.com/"http://example.com/"
Can anyone shed some light on the reason for this?

Answer 1

You shouldn't \-escape your " when you're using ' to surround the string as a whole. This couldn't create that output itself, but it might confuse a parser somewhere down the line, producing the problem. Try this instead:
echo 'Example.com<br />';

Answer 2

Use PHP to output dynamic data and leave the HTML out of it. This will save you hours of quotation frustration
?>
Example.com<br />
<?php
// carry on with the PHP

Answer 3

echo 'Example.com<br />';
outputs
Example.com<br />
The backslashes are included in the final output and most likely trip up the HTML parser.

Answer 4

You're escaping the double quotes. It isn't necessary when using single quotes and vice-versa.
<?php
echo 'Example.com<br />';
?>

Answer 5

The above code outputs the link as:
http://example.com/"http://example.com/"
No, it doesn't produce that output.
This is what you see in the browser when you put the cursor over the link and when you click on the link. It's part of the browser's job to resolve the relative and incomplete links, but what it shows to the user is, most of the times, not what it is written in the HTML code.
Use the browser's "View Source" functionality to see the HTML generated by your code.
The (invalid) HTML produced by your code is:
Link URL - Single Quotes<br />
The browser interprets \"http://example.com\" as the value of the href attribute. The HTTML attribute values can be either enclosed in quotes (") or apostrophes (') or unquoted at all and the quoting character must be the first non-space character after the equal sign (=). Because it finds a backslash (\) after the equal sign, it concludes the attribute value is not quoted and read everything until the first whitespace or until the tag ends (>) as the attribute's value.
The value \"http://example.com\" is not a valid URL and the browser handles it as an incomplete URL. An incomplete URL needs to be resolved to a complete URL in order to be used. It doesn't look like a relative URL (doesn't start with ..), it doesn't look like an absolute path without a host name either (doesn't start with /). The only way to resolve it is to treat it as a file name located in the same directory as the page that is currently loaded. Chances are that your offending code runs in a page located in the root of your website (http://example.com/index.php, for example).
I won't provide a fix for your problem here. The question already have plenty of answers that provide you various ways to avoid this happen.
However, take a look at the strings documentation page in the PHP manual. All you need to know is explained there.