passing Javascript variable to PHP on form submission

Question

This question follows from my previous question counting the rows in html table using php. Since I got no working solution, I want to try a new way but dont know how to implement it. I assign unique ID to each dynamic row added using Javascript. So the count variable in Javascript stores the number of rows present in HTML table. When i submit the form, it is processed by savedata.php. Is it possible to automatically pass the Javascript variable count to savedata.php each time the form is submitted.

Following is a short version of my Javascript file that is used to create unique IDs for elements of dynamically created rows.

var count=2;

function addRow()
{


var table=document.getElementById("studenttable");
var row=table.insertRow(-1);
var cell15=row.insertCell(14);

var ipt8 = document.createElement('input');
    ipt8.setAttribute("type", "hidden");
    ipt8.id = "text" + count; 
    ipt8.name = "htmlrow[]";      
    ipt8.value = count;        
    cell15.appendChild(ipt8);
count++;
}

Each time a new row is added, count increments, so just passing it to the PHP file will allow to get the number of rows in HTML table. I want to do it automatically each time the form is submitted.

Answer 1

Add this inside your form..

<input name="NumRows" id="NumRows" type="hidden" value="0"/>

And then modify your JS to update the value...

document.getElementById("NumRows").value = count;

Then, in your PHP you can do...

$NumRows = $_REQUEST['NumRows'];

Note that if for some reason NumRows isn't passed with the form (unlikely here but possible elsewhere) then you should do this in PHP...

$NumRows = isset($_REQUEST['NumRows'])?$_REQUEST['NumRows']:0;

Which means "If $_REQUEST['NumRows'] is set, use it, otherwise set $NumRows to 0"