Apelare functie Ajax la inchidere pagina

Pentru a apela o functie Ajax cand pagina e inchisa, aplicati evenimentul beforeunload la obiectul "window", care sa apeleze functia ajax cand evenimentul este emis.
- Cererea ajax trebuie facuta in mod sincron (synchronous).

<script>
// sends data to a php file, via POST, when page is closed
function pageClosed() {
 var request = (window.XMLHttpRequest) ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP'); // XMLHttpRequest object
 var data ='name=val'; //data with name and value to send to your_script.php
 request.open('post', 'your_script.php', false); //false - to make synchronous request

 request.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
 request.send(data); //sends data

 console.log(data); //for debug to see if code is executed
 return true;
}

//register event emited when page is closed, it calls the pageClosed() function
window.addEventListener('beforeunload', pageClosed);
</script>

- In scriptul php apelat de Ajax se adauga functia ignore_user_abort(true);. Permite rularea scriptului php si dupa ce fereastra browser-ului este inchisa.

Inregistrare timp petrecut de utilizatori pe site

Iata o aplicatie practica a codului dat mai sus.
Urmatorul script inregistreaza intr-un fisier pe server timpul petrecut de utilizatori pe site (in format json). Aici se inregistreaza utilizatorul dupa IP.

1. Adaugati urmatorul script ajax in paginile din site:

<script>
var start_time = Math.floor(Date.now() /1000);

// sends to php the number of seconds the user spend on time
function pageClosed() {
 var request = (window.XMLHttpRequest) ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP'); // XMLHttpRequest object
 var data ='tms='+(Math.floor(Date.now() /1000) - start_time); //data to send to reg_time.php
 request.open('post', 'reg_time.php', false); //false - to make synchronous request

 request.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
 request.send(data); //sends data

 console.log(data); //for debug to see if code is executed
 return true;
}

//register event emited when page is closed, it calls the pageClosed() function
window.addEventListener('beforeunload', pageClosed);
</script>

2. Adaugati urmatorul cod intr-un fisier php: "reg_time.php".

<?php
ignore_user_abort(true);

if(isset($_POST['tms'])){
 $tms = intval($_POST['tms']);
 $user = $_SERVER['REMOTE_ADDR']; //here we use the ip
 $file ='reg_time.json';
 $f_data =[];

 //add the $user and $tms in json format in $file
 if(!file_exists($file)){
 $f_data[$user] = $tms;
 } else {
 $f_data = json_decode(file_get_contents($file), true);
 if(isset($f_data[$user])) $f_data[$user] = $f_data[$user]+ $tms;
 else $f_data[$user] = $tms;
 }

 file_put_contents($file, json_encode($f_data));
}

3. Urmatorul cod php poate fi utilizat pentru a citi si afisa datele inregistrate in "reg_time.json":

<?php
$file ='reg_time.json';
$f_data =[];

if(file_exists($file)) $f_data = json_decode(file_get_contents($file), true);

foreach($f_data as $k=>$v){
 echo '<br>'. $k.' = '.$v.' seconds';
}

<<-Multiple Select Dropdown List .. -- Preluare sir JSON in ..->>

Un Test simplu in fiecare zi

HTML

CSS

JavaScript

PHP-MySQL

Engleza

Spaniola

Ce tag se foloseste pentru a adauga liste in elemente <ul> si <ol>?

<ul>
 <li>http://coursesweb.net/html/</li>
 <li>http://www.marplo.net/html/</li>
</ul>

Care valoare a proprietatii "display" seteaza elementul ca tip bloc si afiseaza un punct in fata?

block list-item inline-block

.some_class {
  display: list-item;
}

Care instructiune JavaScript transforma un obiect in sir JSON.

JSON.parse() JSON.stringify eval()

var obj = {
 "courses": ["php", "javascript", "ajax"]
};
var jsonstr = JSON.stringify(obj);
alert(jsonstr);    // {"courses":["php","javascript","ajax"]}

Indicati clasa PHP folosita pentru a lucra cu elemente HTML si XML in PHP.

stdClass PDO DOMDocument

$strhtml = '<body><div id="dv1">CoursesWeb.net</div></body>';
$dochtml = new DOMDocument();
$dochtml->loadHTML($strhtml);
$elm = $dochtml->getElementById("dv1");
echo $elm->nodeValue;    // CoursesWeb.net

Indicati forma de Prezent Continuu a verbului "to live" (a trai /a locui)

lived living liveing

I`m living here.
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Care este forma de Gerunziu (sau Participiu Prezent) a verbului "vivir" (a trai /a locui)?

vivió vivido viviendo

Estoy viviendo aquí.
- Traiesc /Locuiesc aici.