javascript replace allowed html tags

Question

I need to use javascript to remove all html tags, except for those I explicitly allow. I have a form that only allows the following tags and their respective end tags:

<b> <strong> <i> <em> <u> <br> <pre>
<blockquote> <ol> <ul> <li> 
<a href="http://www.somesite.com">link</a>

All other markup should be removed. I have been searching but I have only found instances where all tags are removed or a single tag is removed. Can this be done simply? I cannot use PHP, must be javascript. Any solutions?

Thanks!

Answer 1

so sipping all form of security witch im gessing is why you are doing it in the first place

you can put the content in a div and call

$('#container :not(b, strong, em, u, br, pre, blockquote, ol, ul, li, a)').remove();
var res = $("#container").html();

Answer 2

jQuery.fn.removeTags = function()
{
    this.each(function()
    {
        if(jQuery(this).children().length == 0)
        {
            jQuery(this).replaceWith(jQuery(this).text());
        }
        else
        {
            jQuery(this).children().unwrap();
        }
    });
    return this;
};

jQuery("#container").find(":not(b, strong, i, em, u, br, pre, blockquote, ul, ol, li, a)").removeTags();

Make sure the container is nothing higher than the body tag. Or you might have issues when it takes out head , html , script etc. tags.

Also if you want the :not could be a list and you could:

var mylist = ["b" ,"strong", ... etc. etc.];
jQuery(":not(" + mylist.join(", ") + ")").removeTags();

Or even put this in the removeTags function. (the possibilities are endless ... )

EDIT: as some have noted in the comments: Javascript can be turned off. The other thing is I assumed you wanted to keep all the inner information. If not then just a remove() will suffice as megakorre suggests.

Answer 3

As pointed out in the comments, this can't be done securely. It will be very easy to to circumvent the javascript filter. This must be implemented server side.