2

I have a file called: file.php

contained in this file is the following code:

<script type="text/javascript">
        //....
        var sumJS = 10;
    <?php $sumPHP = sumJS  ?>
</script>
    <?php echo "Sum = " . $sumPHP ?>

How can I assign sumJS for $sumPHP?

If I would like to make this conversely then I would write:

  $sumPHP = 10;
<script type="text/javascript">
    var sumJS;
    sumJS = <?php echo $sumPHP ?>;
    alert(sumJS);
</script>

But how can I re-make this for my problem?

Ryan Stone
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Gryz Oshea
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4 Answers4

5

Javascript can change the variables of PHP and vice versa.

Here is an example of that.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Untitled Document</title>
</head>

<body>
<?php $aphp=1 ?>

<script "text/javascript">document.write("<?php $aphp=2 ?>")
var ajava=1;</script>


<?php echo "aphp= $aphp"; echo "<br>";
echo "<script \"text/javascript\">ajava=2;</script>"
?>
<script "text/javascript">document.write("ajava= "); document.write(ajava)</script>
</body>
</html>

What if I want to assign a php variable to a java variable and vice versa The above showed that you can assign values to java in php and vice versa by simply writing out an assignment using echo in php and document.write in java. That is how you assign a value.

Mixing actual variables between php and java is not much more complicated. What you do is write an assignment in the language you need to get the value of a variable from and assign it to a variable in the other language. Here is an example of that.

Assign php to java

<?php echo "<script type='text/javascript'>javasum=$phpsum</script>" ?>

assign java to php can be done in two ways

<script type='text/javascript'>var str="<?php $phpsum=";
str=str+javasum; str=str+" ?>";
document.write(str);
</script>

or more conveniently

javasum=<?php echo $phpsum ?>;

Mixing php and javascript to do things other than variable assignments

Javascript can also be mixed in the phpcode to do a javascript function in the phpcode. Say you wanted to use javascript to highlight text only if a condition is met in the php code. But to do this you need to echo the javascript code section. Also use the escape character, \' to include quotes in a echo command. Here is an example of this

Before you get started be sure php content type is in html. In dreamweaver site editor software, a header to do this is automatically included.

    <p><span id="htext">htext</span></p>


  <?php 
$a=5;
echo "<h3> hello world</h3>";

if ($a==5) {
echo "<script type=\"text/javascript\">";
echo "document.getElementById(\"htext\").style=\"background-color:yellow\"";
echo "</script>";
}
?>
<p>is a=5</p>
<p><?php echo $a ?>&nbsp; </p>
rauprog
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2

You're just missing tags

<?php
$sumPHP = 10;
?>
<script type="text/javascript">
var sumJS;
sumJS = <?php echo $sumPHP ?>;
alert(sumJS);
</script>

demo

genesis
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    You're missing the point. His question was about doing the opposite: > How can I assign sumJS for $sumPHP ? – Nasreddine Oct 23 '11 at 19:18
2

$sumPHP is a server-side value, which will be evaluated on the server. Then the server generates page content and sent it to the client. Then browsers receive the page content and evaluate client-side value sumJS.

So you can never assign sumJS for $sumPHP because $sumPHP is calculated before sumJS.

But can do this to show the page:

<?php echo "Sum = "?><script type="text/javascript">document.write(sumJS);</script>

or rather

<script type="text/javascript">document.write('Sum = ' + sumJS);</script>
Luo
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0

Sorry that at the moment I do not have the time to write an example. But I believe that this idea will work. Maybe someone here can do a quick test.

Just create a hidden element with a unique id, say a span with id="uniqueBufferForCommunicatingBetweenPHPandJS" and style="display:none". Then, with the JS part of the code, write the result into this span by using

document.getElementById("uniqueBufferForCommunicationBetweenPHPandJS").innerHTML = XXX;

You can even write XXX in the form of JSON.

Afterwards, you can use something in PHP like

$bufferspan = $dom->getElementById('uniqueBufferForCommunicationBetweenPHPandJS');

to get the span, and read its content, probably by using

$avariable = $dom->ownerDocument->saveHTML($avariable);

and then interpret the result stored in $avariable. I am not totally sure about the last PHP code.

梁國淦
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