var num=2;
  function addTr(){
    var target=document.getElementById('tbo');
    
    var tr=elem('tr',{id:'tr'+num},{backgroundColor:'#66CCFF'},'');
    
    var td=elem('td',{width:'20%',backgroundColor:'#66CCFF'},'');
      td.appendChild(elem('input',{type:'text',size:'6',id:'bokno'+num,name:"bokno"+num},'','',{onchange:'getBook('+num+')'}));
      td.appendChild(document.createTextNode(" "));
      td.appendChild(elem('input',{type:'button',id:'searchbook'+num,size:'6',value:'查詢'},'','',{onclick:'window.open(\'sale_search.asp?choice='+num+'\');'}));
       
    tr.appendChild(td);
    
    var td=elem('td',{width:'10%',backgroundColor:'#66CCFF'},'');
    td.appendChild(elem('span',{id:"author"+num,name:"author"+num},'',''));
    
    tr.appendChild(td);
    
    var td=elem('td',{width:'36%',backgroundColor:'#66CCFF'},'');
    td.appendChild(elem('span',{id:"bokname"+num,name:"bokname"+num},'',''));
    
    tr.appendChild(td);
    
    var td=elem('td',{width:'8%',backgroundColor:'#66CCFF'},'');
    td.appendChild(elem('input',{type:'text',size:'4',id:"count"+num,name:"count"+num},'',''));
    
    tr.appendChild(td);
    
    var td=elem('td',{width:'16%',backgroundColor:'#66CCFF'},'');
    td.appendChild(elem('input',{type:'text',size:'10',id:"teacher"+num,name:"teacher"+num},'',''));
    
    tr.appendChild(td);
    
    var td=elem('td',{backgroundColor:'#66CCFF'},'');
    td.appendChild(elem('input',{type:'text',size:'18',id:"classname"+num,name:"classname"+num},'',''));
    
    tr.appendChild(td);
    
    
    target.appendChild(tr);
    
    num++;
  }
  function deleteTr(){
    if(num>2){
      num--;
      var target=document.getElementById('tbo');
      target.removeChild(document.getElementById('tr'+num));
    }
  }

function elem(name, attrs, style, text,events) {
    var e = document.createElement(name);
    if (attrs) {
      for (key in attrs) {
        if (key == 'class')
          e.className = attrs[key];
        else if (key == 'id')
          e.id = attrs[key];
        else
          e.setAttribute(key, attrs[key]);
      }
    }

    if(events)  
      for (key in events){
        if(document.all)
          e.setAttribute(key, new Function(events[key]));
        else
          e.setAttribute(key, events[key]);
      }
    if (style)  for (key in style) e.style[key] = style[key];
    if (text)   e.appendChild(document.createTextNode(text));
    return e;
}



function getEle(str){
  return document.getElementById(str);
}

function isBooksRowEmpty(i){

  if(getEle('bokno'+i)&&getEle('bokno'+i).value!="") return false;
  
  if(getEle('count'+i)&&getEle('count'+i).value!="") return false;
  if(getEle('teacher'+i)&&getEle('teacher'+i).value!="") return false;
  return true;
  
}

function checkValue(id,str,type){
  
    str=trim(str);
  
  	var telreg = /^[0-9\-]{0,}$/;

    if(getEle(id)){
      if(type==0){
        if(getEle(id).value=="")
	      {
		      alert(str);
		      getEle(id).focus();
		      return false;
	      }		
      }else if(type==1){
        if(getEle(id).selectedIndex==0)
	      {
		      alert(str);
		      getEle(id).focus();
		      return false;
	      }	
      }else if(type==2){
        if(!telreg.test(getEle(id).value))
	      {
		      alert(str);
		      getEle(id).focus();
		      return false;
	      }
      }
      return true;
    }else{
        return false;
    }
}

function trim(str)
{
   return str.replace(/^\s*|\s*$/g,"");
}


var request=getXMLHttpRequest();

function getBook(index){
    
    if(getEle('bokno'+index).value==""){
        getEle('bokname'+index).innerHTML="";
        getEle('author'+index).innerHTML="";
        return false;
    }
    if(!getEle('bokno'+index)) return false;
    var bokno=getEle('bokno'+index).value;
    
    var url="books_sub.asp?getBook=y&bokno="+bokno;
    request.open("GET", url, true);
    request.onreadystatechange =new Function("setData('"+index+"')");
    request.send(null);
}

function setData(index){
    var target= getEle('bokname'+index);
    if (request.readyState == 4) {
        if (request.status == 200) {
            if(request.responseText=='n'){
                target.innerHTML='此書號不在資料庫內';
                getEle('author'+index).innerHTML="";
            }else{
                var ary=request.responseText.split(",");
                getEle('author'+index).innerHTML=ary[0];
                target.innerHTML=ary[1];
            }
        } else{
            alert("status is " + request.status);
            target.innerHTML=request.responseText;
        }
    }
}


function getXMLHttpRequest(){
        var request;
       try {    
       request = new XMLHttpRequest();
       } catch (trymicrosoft) {
       try {
         request = new ActiveXObject("Msxml2.XMLHTTP");
       } catch (othermicrosoft) {
         try {
        request = new ActiveXObject("Microsoft.XMLHTTP");
         } catch (failed) {
        request = false;
         }
       }
       }

       if (!request)
       alert("Error initializing XMLHttpRequest!");
        return request;
}