通过不带表格的帖子将javascript变量发送到php脚本

Question

I know there are quite a few questions like mine, but I'm attempting to pass a javascript variable to a php script using AJAX. Can anyone point out what I'm doing wrong? Can't seem to figure it out. My javascript on original page:

var myvariable = document.documentElement.innerHTML;
// send variable to server via ajax here  
$.ajax({
   url: 'myphp.php',
   data: { myvariable : myvariable },
   type: 'POST',
   success: function(result) {
    alert("success!");
       }
});

and then to receive on the 'myphp.php' page:

<?php
if(isset($_POST['myvariable']))
{
$myvariable = $_POST['myvariable'];
}
?>

I'm trying to do this without using a form submit - I just want it to send the variable via ajax on page load. Attempting to echo or print the variable $myvariable results in a blank page. Also trying to use this variable in an API call gives me a warning that the field is blank.

Answer 1

I can see what you want to do but unfortunately its logic is misplaced.

PHP loads before Javascript since the server parses it before sending to your browser. So $myvariable has no value until it receives it from the AJAX request, which doesn't come until after the page has actually loaded. Since the new version of the page isn't being re-requested, you don't see anything new appear.

You need a way to communicate the variable from the PHP file back to the browser dynamically. This is done using JSON or something similar to send variables back to Javascript directly for parsing in the browser.

Once you have the JSON library on your server, you'll set the dataType: json in your Javascript and in your PHP you call json_encode($responseData); .

Oh yeah and like the others said:

var myvariable = document.getElementByID('idforelement');

Answer 2

Read this to make ajax call : jQuery Ajax

And use document.getElementByID('element_id').innerHTML OR document.getElementByName(' ').innerHTML to get element's innerHTML value.