How to get JavaScript value in PHP?

Get JavaScript Variable Value in a PHP Variable?

• I have this JavaScript function which is getting a value from a select option in HTML: <script type="text/javascript"> function showUser(str) { if (str=="") { document.getElementById("txtHint").innerHTML=""; return; } if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari xmlhttp=new XMLHttpRequest(); } else {// code for IE6, IE5 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4 && xmlhttp.status==200) { var str=xmlhttp.responseText; var splitstr=str.split('||'); document.getElementById("txtHint").innerHTML=splitstr[0]; document.getElementById("txtval").innerHTML=splitstr[1]; } } xmlhttp.open("GET","getdetails.php?q="+str,true); xmlhttp.send(); } </script> Now, str is the JavaScript variable I want to take its value and put it into a PHP variable. I am using this, but it is not working: $grade = "<script language=javascript>document.write(str);</script>"; echo $grade; What is the correct way to do this?

• Answer:

  PHP runs on a web server, so it will only execute when the page loads. So the above statement will not work as it runs within the function which is called after page load. To achieve what you want, you can send str to a php file via ajax call and store it in a session variable. & then whenever you need the variable call another ajax function which will retrieve the session value.