update.js

java结合ajax编写的简易留言本

  var update_http_request = false;

  function update_send_request(url)
  {
    update_http_request = false;
    if(window.XMLHttpRequest)
    {
      update_http_request = new XMLHttpRequest();
      if (update_http_request.overrideMimeType)
      {
        update_http_request.overrideMimeType('text/xml');
      }
    }
    else if (window.ActiveXObject)
    {
      try
      {
        update_http_request = new ActiveXObject("Msxml2.XMLHTTP");
      }
      catch (e)
      {
        try
        {
          update_http_request = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {}
      }
    }
    if (!update_http_request)
    {
      window.alert("不能创建XMLHttpRequest对象实例.");
      return false;
    }
    update_http_request.onreadystatechange = update_processRequest;
    update_http_request.open("GET", url, true);
    update_http_request.send(null);
  }

  function update_processRequest()
  {
    if (update_http_request.readyState == 4)
    {
      if (update_http_request.status == 200)
      {
        update_init(update_http_request.responseXML);
      }
      else
      {
        alert("您所请求的页面有异常。");
      }
    }
  }

  function update_init(item)
  {
    //alert(item.text);
    var constants = item.getElementsByTagName("constants")[0];

    //var title = constants.getElementsByTagName("title")[0];
    //var copyright = constants.getElementsByTagName("copyright")[0];
    //var password = constants.getElementsByTagName("password")[0];
    //var imgs = constants.getElementsByTagName('image');
    var infos = constants.getElementsByTagName('info');
    var currentPage = constants.getElementsByTagName("currentpage")[0].text;
    var sum = constants.getElementsByTagName("sum")[0].text;
    var num = constants.getElementsByTagName("num")[0].text;

    var len = infos.length;
    for(var i=0; i<len; i++)
    {
      //alert(infos[i].text);
      document.getElementById("info"+i+"0").style.display="";
      document.getElementById("info"+i+"1").style.display="";
      var id = infos[i].getElementsByTagName('id')[0].text;
      var username = infos[i].getElementsByTagName('username')[0].text;
      var emailmessage = infos[i].getElementsByTagName('emailmessage')[0].text;
      var homepage = infos[i].getElementsByTagName('homepage')[0].text;
      var img = infos[i].getElementsByTagName('img')[0].text;
      var contentformat = infos[i].getElementsByTagName('contentformat')[0].text;
      var dateformat = infos[i].getElementsByTagName('dateformat')[0].text;
      var reply = infos[i].getElementsByTagName('reply')[0].text;
/*
      alert("id : "+id+
		  "\nusername : "+username+
		  "\nemailmessage : "+emailmessage+
		  "\nhomepage : "+homepage+
		  "\nimg : "+img+
		  "\ncontentformat : "+contentformat+
		  "\ndateformat : "+dateformat+
		  "\nreply : "+reply);

      alert(contentformat+"|"+contentformat.replace(/&lt;/g,"<"));
*/
      document.getElementById("contentformat"+i).innerHTML = contentformat.replace(/&lt;/g,"<");
	  //document.getElementById("contentformat"+i).innerHTML = "<marquee>asdf</marquee>";
      document.getElementById("username"+i).innerHTML = username.replace(/&lt;/g,"<");
      document.getElementById("img"+i).src = img;
      if(reply=='')
      {
        document.getElementById("reply"+i+"0").style.display="none";
      }
      else
      {
        document.getElementById("reply"+i+"0").style.display="";
        document.getElementById("reply"+i+"1").innerHTML = reply.replace(/&lt;/g,"<");
      }
      document.getElementById("dateformat"+i).innerHTML = dateformat.replace(/&lt;/g,"<");
      document.getElementById("homepage"+i).innerHTML = homepage.replace(/&lt;/g,"<");
      document.getElementById("emailmessage"+i).innerHTML = emailmessage.replace(/&lt;/g,"<");
	  document.getElementById("viewip"+i).setAttribute("href", "viewip.html?id="+id);
	  document.getElementById("reply"+i).setAttribute("href", "javascript:openChild(\"reply.html?id="+id+"\")");
	  document.getElementById("delete"+i).setAttribute("href", "javascript:openChild(\"delete.html?id="+id+"\")");

      //alert();
    }
    for(var i=len; i<6; i++)
    {
      document.getElementById("info"+i+"0").style.display="none";
      document.getElementById("info"+i+"1").style.display="none";
    }

    //var sel = document.boardForm.img.options;
    //for(var i=0; i<imgs.length; i++)
    //{
    //  sel[i] = new Option(imgs[i].text,i);
    //}

    //document.title = title.text;
    //document.getElementById('title2').innerText = title.text;
    //var tmp = copyright.text;
    //tmp = tmp.replace(/&gt;/g,'>');
    //tmp = tmp.replace(/&lt;/g,'<');
    //document.getElementById("copyright").innerHTML = tmp;

    if(num>1)
    {
      document.getElementById("status0").style.display="";
      document.getElementById("status1").style.display="none";
      document.getElementById("sum0").innerText = sum;
      document.getElementById("num").innerText = num;
      var pageInfo = "";
      for(var i=0; i<num; i++)
      {
        if(i == currentPage)
        {
          pageInfo += "<font color=\"gray\">第" + (i+1) + "页</font>";
        }
        else
        {
          pageInfo += "<a href=\"javascript:update('" + i + "')\">第" + (i+1) + "页</a>";
        }
      }
      document.getElementById("page").innerHTML = pageInfo;
    }
    else
    {
      document.getElementById("status0").style.display="none";
      document.getElementById("status1").style.display="";
      document.getElementById("sum1").innerText = sum;
    }
  }

  function update(currentPage)
  {
    update_send_request("boardServlet?currentPage=" + currentPage);
  }