mdshare Posted April 6, 2008 Posted April 6, 2008 JavaScript cannot actively read variables from the server, but when a page loads, PHP can pass variables to JavaScript by writing to the page the JavaScript is on. <?php $username = "Snib"; ?> ... <script language="javascript" type="text/javascript"> var sStr = "My name is <?php echo $username ?>."; document.write(sStr); </script> ... This code will output this text: ... My name is Snib. ... By editing the JavaScript on the page, PHP can set JavaScript variables. This is very useful for passing database values to JavaScript to compare with a JavaScript variable or number. Let's say that there is a MySQL database called db1, with a table called table1, which has two columns, 'userid' and 'usernum'. To retrieve information about Snib, you can use code like this: <?php $connection = mysql_connect('localhost', 'username', 'password'); $sql = mysql_select_db('db1', $connection); $userid = "Snib"; $query = "SELECT * FROM `table1` WHERE userid='$userid'"; $result = mysql_query($query); $data = mysql_fetch_assoc($result); $usernum = $data['usernum']; ?> <script language="javascript" type="text/javascript"> var userid = "<?php echo $userid; ?>"; var usernum = "<?php echo $usernum; ?>"; //if usernum is less than or equal to 50 if (usernum <= 50) { alert("You are not allowed on this page, " + userid); setTimeout('window.location = "otherpage.php"', 3000); // user leaves in 3 seconds } else { alert('Welcome to this page, ' + userid); } </script> <?php mysql_close($connection); ?> Although setting JavaScript variables with PHP is helpful, it cannot always be done. For instance, PHP cannot modify external .js documents temporarily. It changes them for good. Reference: MySQL with PHP: http://php.net/mysql JavaScript: http://javascript.com http://msdn.microsoft.com/library/default.asp (JScript and DHTML) Quote
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