Given a string of html code, how can I go through every tag and remove ones that is not in my whitelist (in JQuery)?
var whitelist = ['a','div','img', 'span'];

var canvas = '<div>'+canvas_html+'</div>';
        var blacklist = ['script','object','param','embed','applet','app','iframe',
        'form','input', 'link','meta','title','input','button','textarea'
        'head','body','kbd'];
        blacklist.forEach(function(r){
            $(canvas).find(r).remove();
        });
        canvas_html = $(canvas).get('div').html();

var whitelist = ['a','div','img', 'span'];
var output = $('<div>'+canvas_html+'</div>').find('*').each(function() {
  if($.inArray(this.nodeName.toLowerCase(), whitelist)==-1) {
    $(this).remove();
  }
}).html();
// output contains the HTML with everything except those in the whitelist stripped off

$(canvas).find(':not(' + whitelist.join(', ') + ')').remove().html();