How to send textarea who contains html using Jquery $.ajax

Question

I have made changes on my comments for add TinyEditor(WYSIWYG). to send data i use this jquery function

function AddComent(){
    var formulario="#send_coment";
    var url = "comentario.php";
    var destino="#leercomentarios";
    $.ajax({
            type: "POST",
            url: url,
            data: $(formulario).serialize(),
            success: function(data)
                {
                    $(destino).html(data);
                }
        });
    envio_comentario.reset();
    $("#iframe_a_limpiar").contents().find("body").html('');
}

I have tried to set json data datatype, and more option that i have read in other places, but my log say same concept, error 403, it only happens depending the html entities to send, if i use the editor only with one or none style it works.

By other side, i have tried to use tinyeditor on pure PHP HTML, and it works fine.

Anyone know where is the problem on my script.

---

(thanks to Quentin for all) The problem is apache security mod, but i cant change it, i have seening a solution like this

function awesome() {
        elements = document.forms[0].elements;
        for(var i = 0; i < elements.length; i++) {
            switch(elements[i].name) {
                case "ads":
                case "shortDescription":
                case "template":
                case "questions":
                case "salary":
                case "jobs":
                    str = elements[i].value;
                    elements[i].value = str.replace(/</g,"#@!");
                    break;
            }
        }
        return true;    
    }

How can i convert this code to do with only with textarea and send all form at same time?