function select_category(category){
    if(category=='cineaste'){
        document.form_header.simpleField.value='creator_name';
        document.getElementById('select_cineaste').style.color='#ffffff';
        document.getElementById('select_film').style.color='#000000';
        document.getElementById('select_keyword').style.color='#000000';
    }
    else if(category=='film'){
        document.form_header.simpleField.value='work_title';
        document.getElementById('select_cineaste').style.color='#000000';
        document.getElementById('select_film').style.color='#ffffff';
        document.getElementById('select_keyword').style.color='#000000';
    }
    else if(category=='keyword'){
        document.form_header.simpleField.value='work_description';
        document.getElementById('select_cineaste').style.color='#000000';
        document.getElementById('select_film').style.color='#000000';
        document.getElementById('select_keyword').style.color='#ffffff';
    }
}