function changeColor(color){
    eventSource=event.srcElement
    if (eventSource.tagName=="TR"||eventSource.tagName=="TABLE"){
        return
    }
    while(eventSource.tagName!="TD"){
        eventSource=eventSource.parentElement
    }
    eventSource.style.backgroundColor=color
}
function restoreColor(color){
    eventSource.style.backgroundColor=color
}