function catChangeHandler(element, json) {
    var theValue = element.value;
    var theType = '';

    $.each(json, function(index, item) {
        if (item.category == theValue) {
            theType = item.type;
        }
    });

    if (theType == 'survey') {
        researchField = document.getElementById("container_research_link");
        subjectField = document.getElementById("container_research_subject");
        dateField = document.getElementById("container_research_date");
        uploadField = document.getElementById("container_contact_attachement");
        uploadField2 = document.getElementById("container_attachement_webshop");
        mailSubjectField = document.getElementById("container_contact_subject");

        researchField.style.display = 'block';
        subjectField.style.display = 'block';
        dateField.style.display = 'block';
        uploadField.style.display = 'block';
        uploadField2.style.display = 'none';
        mailSubjectField.style.display = 'none';
    } else if (theType == 'webshops') {
        researchField = document.getElementById("container_research_link");
        subjectField = document.getElementById("container_research_subject");
        dateField = document.getElementById("container_research_date");
        uploadField = document.getElementById("container_contact_attachement");
        uploadField2 = document.getElementById("container_attachement_webshop");
        mailSubjectField = document.getElementById("container_contact_subject");

        researchField.style.display = 'none';
        subjectField.style.display = 'none';
        dateField.style.display = 'none';
        uploadField.style.display = 'none';
        uploadField2.style.display = 'block';
        mailSubjectField.style.display = 'block';
    } else {
        researchField = document.getElementById("container_research_link");
        subjectField = document.getElementById("container_research_subject");
        dateField = document.getElementById("container_research_date");
        uploadField = document.getElementById("container_contact_attachement");
        uploadField2 = document.getElementById("container_attachement_webshop");
        mailSubjectField = document.getElementById("container_contact_subject");

        researchField.style.display = 'none';
        subjectField.style.display = 'none';
        dateField.style.display = 'none';
        uploadField.style.display = 'block';
        uploadField2.style.display = 'none';
        mailSubjectField.style.display = 'block';
    }

}