147

I am trying to get a PHP array variable into a JavaScript variable.

This is my code:

<html>
    <head>
        <script type="text/javascript">
              function drawChart(row,day,week,month,date)
              {
                  // Some code...
              }
        </script>
    </head>

    <body>
        <?php
            for($counter = 0; $counter<count($au); $counter++)
            {
                switch($au[$counter]->id)
                {
                    case pageID.'/insights/page_active_users/day':
                        $day[] = $au[$counter]->value;
                    break;
                    case pageID.'/insights/page_active_users/week':
                        $week[] = $au[$counter]->value;
                    break;
                    case pageID.'/insights/page_active_users/month':
                        $month[] = $au[$counter]->value;
                    break;
                }
            }
        ?>
        <script>
            drawChart(600/50, '<?php echo $day; ?>', '<?php echo $week; ?>', '<?php echo $month; ?>', '<?php echo createDatesArray(cal_days_in_month(CAL_GREGORIAN, date('m',strtotime('-1 day')), date('Y',strtotime('-1 day')))); ?>');
        </script>
    </body>
</html>

I can't get value of the PHP array.

How do I fix this problem?

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0

4 Answers 4

Reset to default
216

Use JSON.

In the following example $php_variable can be any PHP variable.

<script type="text/javascript">
    var obj = <?php echo json_encode($php_variable); ?>;
</script>

In your code, you could use like the following:

drawChart(600/50, <?php echo json_encode($day); ?>, ...)

In cases where you need to parse out an object from JSON-string (like in an AJAX request), the safe way is to use JSON.parse(..) like the below:

var s = "<JSON-String>";
var obj = JSON.parse(s);
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7 Comments

What would be the disadvantage of simply writing var obj = <?php echo json_encode($php_variable); ?>;? Won't PHP encode the JSON object securely in a way that it's parsable by the script?
Yes, that is the way. But my intention was to put across JSON.parse() as one safe way to parse from string. Thanks for pointing, I will edit my post.
var data = <?php echo json_encode($registos); ?>; returns the error: SyntaxError: Unexpected token <
i am getting this error, too (Unexpected token <)
@RemusRigo & Nuno: Just a guess, are you opening PHP tags within PHP tags? In any case, please post a new question.
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83

You can pass PHP arrays to JavaScript using json_encode PHP function.

<?php
    $phpArray = array(
        0 => "Mon", 
        1 => "Tue", 
        2 => "Wed", 
        3 => "Thu",
        4 => "Fri", 
        5 => "Sat",
        6 => "Sun",
    )
?>

<script type="text/javascript">

    var jArray = <?php echo json_encode($phpArray); ?>;

    for(var i=0; i<jArray.length; i++){
        alert(jArray[i]);
    }

 </script>
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4 Comments

can you help? permission[1]=0 php array becomes object like this "permission":{"1":["0"]}, while permission[0]=0 remains Array.
hey @shyammakwana.me you might have made a nested array, check print_r($array) before json_encode() and see if the array formed is like same as above then it will work fine.
Hi @Tarun thanks for reply, yes my array is like $p[1][0] = 0 ; and it gives object in my JS, it's nested. how to overcome this?
This should be the most upvoted, since this is what OP is asking for
15

Data transfer between two platform requires a common data format. JSON is a common global format to send cross platform data. 

drawChart(600/50, JSON.parse('<?php echo json_encode($day); ?>'), JSON.parse('<?php echo json_encode($week); ?>'), JSON.parse('<?php echo json_encode($month); ?>'), JSON.parse('<?php echo json_encode(createDatesArray(cal_days_in_month(CAL_GREGORIAN, date('m',strtotime('-1 day')), date('Y',strtotime('-1 day'))))); ?>'))

This is the answer to your question. The answer may look very complex. You can see a simple example describing the communication between server side and client side here

$employee = array(
 "employee_id" => 10011,
   "Name" => "Nathan",
   "Skills" =>
    array(
           "analyzing",
           "documentation" =>
            array(
              "desktop",
                "mobile"
             )
        )
);

Conversion to JSON format is required to send the data back to client application ie, JavaScript. PHP has a built in function json_encode(), which can convert any data to JSON format. The output of the json_encode function will be a string like this.

{
    "employee_id": 10011,
    "Name": "Nathan",
    "Skills": {
        "0": "analyzing",
        "documentation": [
            "desktop",
            "mobile"
        ]
    }
}

On the client side, success function will get the JSON string. Javascript also have JSON parsing function JSON.parse() which can convert the string back to JSON object.

$.ajax({
        type: 'POST',
        headers: {
            "cache-control": "no-cache"
        },
        url: "employee.php",
        async: false,
        cache: false,
        data: {
            employee_id: 10011
        },
        success: function (jsonString) {
            var employeeData = JSON.parse(jsonString); // employeeData variable contains employee array.
    });
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1 Comment

too bad the "here" link is now dead.
9

In the following example you have an PHP array, then firstly create a JavaScript array by a PHP array:

<script type="javascript">
    day = new Array(<?php echo implode(',', $day); ?>);
    week = new Array(<?php echo implode(',',$week); ?>);
    month = new Array(<?php echo implode(',',$month); ?>);

    <!--  Then pass it to the JavaScript function:   -->

    drawChart(<?php echo count($day); ?>, day, week, month);
</script>
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2 Comments

what's the point of using Ajax when using PHP, when you can just inject PHP directly into the script?
You can't execute php code on button click without using ajax

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