JS将图片转为base64

var getDataFromImg = function(img) {
        var canvas = document.createElement('canvas');
        var context = canvas.getContext('2d');
        context.drawImage(img, 0, 0 );
        var dataURL = canvas.toDataURL('image/png');

        return dataURL.replace(/^data:image/(png|jpg);base64,/, '');
    }

    var images = document.querySelectorAll('.image');
    var finalArray = {};
    for ( var i=0; i<images.length; i++ )
    {
        //I just filled in array. Depending on what you're grabbing, you may want to fill
        //This with objects instead with text to identify each image.
        finalArray.push(getDataFromDiv(images[i]));
    }
    return finalArray;

https://stackoverflow.com/questions/30833290/fetching-images-with-javascriptresponse-in-cefbrowser-without-downloading-twice