javascript - Export PDF from OpenLayers map with jsPDF

I try to use javascript library JSPDF for export my OpenLayers map but it doesn't work. I create my HTML :

And my Javascript :

$(document).ready(function () {

    var doc = new jsPDF();

    var specialElementHandlers = {
        '#editor': function (element, renderer) {

            console.log(1);
            return true;
        }
    };

    $('#cmd').click(function () {

        var html=$("'#index_map").html();
        console.log (html);
        doc.fromHTML(html, 200, 200, {

            'width': 500,
                'elementHandlers': specialElementHandlers
        });
        doc.save('test.pdf');

    });
});

And when I click on my button I've the message "doc.fromHTML is not a function"

Answer

Use:

doc.fromHTML($('#index_map').get(0), 15, 15, {
    'width': 170, 
    'elementHandlers': specialElementHandlers
});

note the get: doc.fromHTML($('#index_map').get(0)