Pass a PHP array to a JavaScript function

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);

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>

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.
    });