raw-print-server.php

<?php
// RawPrintServer INSTALL "EPSON LX-310 ESC/P" 2481
if ( isset( $_REQUEST['q'] ) ){
    $socket = socket_create( AF_INET, SOCK_STREAM, 0 ) or die( "Error socket\r\n" );
    $result = socket_connect( $socket, "127.0.0.1", 2481 ) or die( "Error connecting\r\n" );
    $message = $_REQUEST['q'];
    socket_write( $socket, $message, strlen( $message ) ) or die( "Error sending\r\n" );
    socket_close( $socket );
    die( strlen( $_REQUEST['q'] ) );
}
?>
<textarea name=q readonly cols=152 rows=25 >{1B}{21}{01}{1B}M{0F}{1B}{C1}{0B}Hello, world!
{0E}Double-width{14}
</textarea>
<button type=button name=button value=button >Print</button>
<script>
document.querySelector( '[name=button]' ).addEventListener( 'click', e=>{
    var http = new XMLHttpRequest();
    http.open( 'POST', 'raw-print-server.php', true );
    http.setRequestHeader( 'Content-type', 'application/x-www-form-urlencoded' );
    http.onreadystatechange = function() {
        if ( http.readyState == 4 && http.status == 200 ) {
            console.log( http.response );
            alert( "Printed: " + http.response + " bytes" );
        }
    }
    var params = 'q=' + encodeURIComponent( document.querySelector('[name=q]').value
        .replace(/\{([0-9a-fA-F][0-9a-fA-F])\}/g, function(m,x){
            return String.fromCharCode(parseInt(x, 16));
        }) );
    http.send(params);
}, false );
</script>