how Start PHP Session when click with jquery

It is not possible to use PHP session directly with jQuery, you need to do an ajax call.

Try this.

Explanation:

• This will capture the value inside the link, do a post to a PHP file and print the data in "result" div without refreshing the page.

(Don't forget to read my observation at the end of the post)

HTML:

<a href='#' id='country'>USA</a>
<br/>
<div id="result"></div>

JS:

​$('#country').click(function(){
    // get the value inside the <a> tag
    var country = $(this).html();
    $.post('process.php', { country:country }, function(data){
        // Everything is Ok, so data won't be 0
        if(data != 0){
           // Print country information
           $('#result').html(data);
        }
    });
});

process.php

<?php

if($_POST() && isset($_POST['country'])){

/* Connect to DB */
$link = mysql_connect('server', 'user', 'pwd');
if (!$link) {
    // No connection
    print(0);
    exit();
}

$db = mysql_select_db('db', $link);
if (!$db) {
    // DB selection error
    print(0);
    exit();
}

/* sanitize the value */
$country = mysql_real_escape_string($_POST['country']);

/* do your query */
$sql = "SELECT * FROM country WHERE country_name = '$country'";
$result = mysql_query($sql);

if(mysql_num_rows($result) > 0){
   while($row = mysql_fetch_array($result)){
      // At this point I am supposing that you stored in your table
      // latitudes and longitudes of countries.
      echo "Latitude is: ".$row['latitude']." Longitude is: ".$row['longitude'];
   }
} else {
  // No results found
  print(0);
}

}

?>​

Observation:

• Try using other way to send the country value to the server.

For example:

if I have:

<a href='#' id='country'>United States of America</a>

In SQL query I will have:

SELECT * FROM country WHERE country_name = 'United States of America';

A better way could be:

<a href='#' id='us'>United States of America</a>

So in my JS I will have to replace var country = $(this).html(); for this:

 //outputs 'us'
 var country = $(this).attr('id');

Then in your SQL query you will get this:

SELECT * FROM country WHERE country_name = 'us';

It is more reasonable to use codes and no names (names are just to show the user, for better understanding because then you will have more problems to sanitize the value for using it with your query and also use functions like trim(); to remove spaces and others). If you do that you will have to change your query to find the country by code:

SELECT * FROM country WHERE country_code = 'us';

Hope this helps :-)