无需提交和保存即可读取所选文件。 PHP - JavaScript

I try to read file (id="file") after selected and return character count to paragraph (id="count"). I want it without submitting, without clicking any other button and without saving. I've tried jquery and "vanilla" javascript. Here is my code with "vanilla":

HTML:

<input type="file" id="file" name="file" onchange="fileCount(this)" />
<p id="count"></p>

Javascript:

function fileCount(file) {

    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) {
            document.getElementById("count").innerHTML = xmlhttp.responseText;

        }
    };
    xmlhttp.open('POST', 'fileCount.php', true);
    xmlhttp.setRequestHeader('X-FileName',file.name);
    xmlhttp.send(file);}

PHP:

if(!empty($_FILES['file'])) {

    if ($_FILES['file']['error'] === 0) {
        $temp = $_FILES['file']['tmp_name'];

        $ext = (explode(".",$temp));
        $ext = end($ext);
        $file = "";
        switch ($ext) {
            case "pdf":
                $text = pdf2text($temp);
                $file = strlen(utf8_decode($text));
                print_r( "<p id='count'>Počet: " . $file . "</p>");
                break;
            case "docx":
                $text = docx2text($temp);
                $file = strlen(utf8_decode($text));
                print_r( "<p id='count'>Počet: " . $file . "</p>");
                break;
            case "odt":
                $text = odt2text($temp);
                $file = strlen(utf8_decode($text));
                print_r( "<p id='count'>Počet: " . $file . "</p>");
                break;
            case "rtf":
                $text = rtf2text($temp);
                $file = strlen(utf8_decode($text));
                print_r( "<p id='count'>Počet: " . $file . "</p>");
                break;
            //case "txt":
                $text = file_get_contents($temp);
                $file = strlen(utf8_decode($text));
                print_r( "<p id='count'>Počet: " . $file . "</p>");
                break;
            default:
                print_r( "Wrong file format" );
        }
    }

}

and nothing is returning. Please help, what is wrong. Thank you