How to work with API via URL?

Question

PHP

if you type a line in the address bar
speller.yandex.net/services/spellservice/checkText...
"page" will display

<SpellResult>
<error code="1" pos="0" row="0" col="0" len="6">
<word>malavi</word>
<s>Malawi</s>
</error>
</SpellResult>

How to get to assign a value between tags <s></s>to some variable?
If you use
speller.yandex.net/services/spellservice/checkText...
then it will simply return
<SpellResult/>Well, there are no errors. How to use such an answer to understand that there is no error?

Answer 1

This is XML. So you need to parse it. Start learning here

Answer 2

php.net/manual/en/simplexml.examples-basic.php

Answer 3

This service has quite intelligible documentation in Russian.
It can work in two modes: XML-/SOAP-interface and JSON- and JSONP-interface.
If you don't know SOAP/XML, use JSON.
Other questions are answered in the documentation.