using for loop value from javascript with php variable

Question

I have this code that executes a for loop in javascript with a php array inside of it. Is there anyway I can use the variable for the loop inside of the php variable for example. This is all inside of php.

echo '<script>
for (var i =0; i<4;i++){

alert("hey"'.$phparr[i].');



}</script>';

I know this will not work because the $phparr is a php variable while the i is a javascript variable is there anyway I can do this?

Answer 1

Try:

<script>    
    var phparr = <?php echo json_encode($phparr); ?>;

    for (i in phparr){

        alert("hey" + phparr[i]);

    }
</script>

PHP is a server side language which means it executes before it reaches the client (browser).

JavaScript is a client side language which means it is executed in the browser (client side).

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Answer 2

You're almost there. In order to access the php array in javascript, you first have to echo out the php array into a javascript array. Try:

$phparr_imploded = implode(',',$phparr);
echo '
    <script>
        var arr = ['.$phparr_imploded.'];
        for (var i =0; i<4;i++){
            alert("hey"+arr[i]);
        }
    </script>
';

If your php array is coming from a database, or contains special characters that javascript may misinterpret, make sure to sanitize before outputting.

Are the objects in your php array strings? If so, you need to surround the objects with escaped quotations BEFORE the implode.

for($i=0; i<count($phparr); $i++){
    $phparr[i] = '"'.$phparr[i].'"';
};

Answer 3

How about storing the PHP array in a Javascript variable and looping through as kpotehin suggests?

<script>
var i = 0, name;
var myArr = <?php echo json_encode($my_array); ?>;

while (name = myArr[i++]){
  alert("hey " + name);
}
</script>

Answer 4

You should make it this way:

var arr = ["<?php echo implode('","',$array); ?>"];
for (var i =0; i<4;i++){
alert("hey"+ arr[i]);
}

Answer 5

Your basic problem is that you are forgetting that the PHP code and the JavaScript code do not execute at the same time. The PHP runs to completion, outputing HTML and JavaScript. Then the browser runs the JavaScript. If the JavaScript needs dynamic access to data in a PHP variable (including an array), then the PHP needs to generate JavaScript declaring the data in a JavaScript structure. That is what all the other answers are doing.