Validate if website exists with AJAX - php

Question

I'm trying to check if a website exists with an ajax call, but I'm not sure I am getting it right. On my page I grab a URL on click
$("#go").click(function() {
var url = $("#url").val();
$.ajax({
type: "POST",
url: "/ajax.php",
data: "url="+url,
success: function(){
$("#start").remove();
},
error: function(){
alert("Bad URL");
}
});
});
a=And then check on ajax.php
$url = $_POST['url'];
ini_set("default_socket_timeout","05");
set_time_limit(5);
$f=fopen($url,"r");
$r=fread($f,1000);
fclose($f);
if(strlen($r)>1) {
return true;
} else {
return false;
}
It seems I am getting SUCCESS no matter what... What am I missing?

Answer 1

It seems I am getting SUCCESS no matter what... What am I missing?
This is extremely pretty straightforward.
Because of this reasons:
// You have no idea what server respond is.
// that is you can't parse that respond
success: function(){
$("#start").remove();
}
Which should be
success: function(respond){
//you don't have to return TRUE in your php
//you have to echo this one instead
if ( respond == '1'){
$("#start").remove();
} else {
//handle non-true if you need so
}
}
In php replace this:
if(strlen($r)>1) {
return true;
} else {
return false;
}
to
if(strlen($r)>1) {
print true; //by the way, TRUE is a constant and it equals to == 1 (not ===)
}
Oh yeah, also don't forget to fix this as well:
data: "url="+url,
to data : {"url" : url}

Answer 2

As Nemoden said, you get a success message even if it returns false.
You need to check the data returned and then remove the element.
for example
$("#go").click(function() {
var url = $("#url").val();
$.ajax({
type: "POST",
url: "/ajax.php",
data: "url="+url,
success: function(response){
if (response == 'whatever you are returning') {
$("#start").remove();
}
},
error: function(){
alert("Bad URL");
}
});
});

Answer 3

Success callback is called whenever server-side script returned an answer (there were no connectivity errors or server-side errors). Is this answering your question?
See the difference:
$("#go").click(function() {
var url = $("#url").val(),
ajax_data = {url: url};
$.post({
"/ajax.php?cb=?",
ajax_data,
function(response){
if (response.status) {
// URL exists
}
else {
// URL not exists
}
$("#start").remove();
},
'json'
});
});
php back-end:
printf('%s(%s)', $_GET['cb'], json_encode(array('status' => (bool)$url_exists)));