/**
 * Get PDF with jQuery AJAX and show it inside an iframe.
 *
 * Using mPDF as PDF generator in PHP, set the output mode to inline:
 *     $mpdf->Output('I');  // where $mpdf is an instance of mPDF
 *
 * HTML demo:
 *     <button id="btn-generate-pdf" class="btn btn-primary">Generate PDF</button>
 *     <hr>
 *     <div id="div-iframe"></div>
 */

var pdf_url = 'http://example.com/generate_pdf';
var div_iframe = $('#div-iframe');

div_iframe.hide();

$(document).ready(function () {
    $('#btn-generate-pdf').click(function () {
        div_iframe.hide();

        if ($('#iframe-pdf').length > 0) {
            $('#iframe-pdf').remove();
        }

        var btn_generate_pdf = $('#btn-generate-pdf');
        var old_text = btn_generate_pdf.text();
        btn_generate_pdf.text('Generating...').addClass('disabled').css('pointer-events', 'none');

        $.ajax({
            url: '',
            type: 'GET',
            processData: false,
            xhrFields: { withCredentials: true },
            success: function () {
                var iframe = $('<iframe id="iframe-pdf" class="iframe-pdf" width="100%" ' +
                    'height="800" frameborder="0"></iframe>');

                iframe.attr('src', pdf_url);
                iframe.load(function () {
                    btn_generate_pdf.text(old_text).removeClass('disabled').css('pointer-events', '');
                    div_iframe.show();
                });

                div_iframe.append(iframe);
            }
        });
    });
});