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PHP Ajax Sample

simong1993

Active Coder
Staff Team
Guardian
Hey all,

im trying to get my head around Ajax. Does anyone have a easy sample script that just connects to the database and updates a echo on the page when something changes. I just need something to take apart and see what makes it tick :D thanks all
 

Ghost

Active Coder
If you are wanting to output JSON it's very easy!
PHP:
<?php
$arrayhere = ["you", "can", "json", "if", "you", "want", "to", "you", "can", "leave", "your", "friends", "behind"];
/*
 $sql = $database->prepare("SELECT * FROM table");
 // execute sql, store result, check num rows, then use json encode of a return arra
*/
exit(json_encode($arrayhere));
?>

You might want to also have a few different return values... like so:
PHP:
$data = array(array("id"=>55, "username"=>"GHOST"), array("id"=>102, "username"=>"malcolm"));
echo json_encode(array("success"=>$data ? true : false, "num_results"=>$data ? count($data) : 0, "data"=>$data, "message"=>$data ? "Fetched data successfully." : "We cannot fetch this information right now."));

I like to use something such as a success boolean (true/false, 1/0, etc)so that I can json_encode a return that has an error or no results:
array("success"=>false, "message"=>"We cannot fetch this information right now.");

When you use AJAX you will do something like this:
JavaScript:
ajax({
    method: "GET",
    url: "fetch.php",
    data: {
        key1: 'hi',
        key2: 5
    },
    success: function(data){ // means AJAX responded
        if(data.success){ } else { } // check if our JSON is reporting error or not
        console.log(data);
        alert(data.message);
    },
    fail: function(data){ // unsuccessful ajax attempt
        console.log(data);
    }
});
This example uses my custom AJAX JS function that I published on Github. Check it out!

Hope this helps! :)
 
Last edited:

simong1993

Active Coder
Staff Team
Guardian
i probably should have expanded a bit more lol. So value is 0 as its not done yet in the database, Python does it thing and updates the database so 0 is say 9.99 now. How would i make it so instead of refreshing the page it would pull the new 9.99 from the database and display it :D I think thats Ajax right lol
 

Ghost

Active Coder
i probably should have expanded a bit more lol. So value is 0 as its not done yet in the database, Python does it thing and updates the database so 0 is say 9.99 now. How would i make it so instead of refreshing the page it would pull the new 9.99 from the database and display it :D I think thats Ajax right lol
Well, AJAX is a part of JavaScript specifically. PHP, Python, or other files just echo / print out information on the page. The JS will fetch the output / results of the file. json encode in PHP for example makes it so the PHP array is compatible with JS.

If you want to fetch a new value of something...
JavaScript:
setInterval(function(){
    // ajax goes here, it will call on a script that returns data or a value
},60000) // repeat every 60 seconds

Then let's imagine you fetch the value from the database in PHP and echo it out:
PHP:
$value = 9.99;
echo $value;

Your AJAX success would be like this, if you're only echoing out the value of it.
JavaScript:
success: function(returndata){
    alert("The new value is " + returndata);
}
 

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