<input id="save" type="button" value="сохранить"  disabled="disabled" /> <input id="del" type="button" value="удалить"  disabled="disabled" />
<input id="check" type="checkbox" onChange="if(this.checked){document.all.save.disabled=false; document.all.del.disabled=false;}else{document.all.save.disabled=true; document.all.del.disabled=true;}" />