view.js

java结合ajax编写的简易留言本

  var view_http_request = false;

  function view_send_request(url, message)
  {
    view_http_request = false;
    if(window.XMLHttpRequest)
    {
      view_http_request = new XMLHttpRequest();
      if (view_http_request.overrideMimeType)
      {
        view_http_request.overrideMimeType('text/xml');
      }
    }
    else if (window.ActiveXObject)
    {
      try
      {
        view_http_request = new ActiveXObject("Msxml2.XMLHTTP");
      }
      catch (e)
      {
        try
        {
          view_http_request = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {}
      }
    }
    if (!view_http_request)
    {
      window.alert("不能创建XMLHttpRequest对象实例.");
      return false;
    }
    view_http_request.onreadystatechange = view_processRequest;
    view_http_request.open("POST", url, true);
	view_http_request.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
	//alert(message);
    view_http_request.send(message);
  }

  function view_processRequest()
  {
    if (view_http_request.readyState == 4)
    {
      if (view_http_request.status == 200)
      {
        //alert(view_http_request.responseText);
        view_init(view_http_request.responseXML);
      }
      else
      {
        alert("您所请求的页面有异常。");
      }
    }
  }

  function view_init(item)
  {
    var viewItem = document.getElementById("view");
    var idItem = document.getElementById("id");
    var ipItem = document.getElementById("ip");
    var successItem = document.getElementById("success");
    var errItem = document.getElementById("err");
    var msgItem = document.getElementById("msg");

    var constants = item.getElementsByTagName("constants")[0];
	//alert("60" + item.text);
	var err = constants.getElementsByTagName("err");
	//alert("64|" + err + "|" + err.length);
	if(err.length == 1)
	{
      viewItem.style.display = "none";
      msgItem.innerText = err[0].text;
      errItem.style.display = "";
	  return;
	}
	else
	{
      //
      viewItem.style.display = "none";
	  successItem.style.display = "";
	  idItem.innerText = constants.getElementsByTagName("id")[0].text;
	  ipItem.innerText = constants.getElementsByTagName("ip")[0].text;
	}

  }

  function view()
  {
    //首先提取信息，并进行验证
    var pageUrl = window.location.toString();//获取当前页的URL，并附给字符串 pageUrl

    var params = pageUrl.split("="); //以 = 为分隔符，将上面获得的 URL 拆分成数组
    var id = params[1]; //取得 = 的后一部分
    var password = document.viewipForm.pass.value;

    var viewItem = document.getElementById("view");
    var idItem = document.getElementById("id");
    var ipItem = document.getElementById("ip");
    var successItem = document.getElementById("success");
    var errItem = document.getElementById("err");
    var msgItem = document.getElementById("msg");

    if(id == "undefine" || id == "" || isNaN(id))
    {
      viewItem.style.display = "none";
      //successItem.style.display = "none";
      msgItem.innerText = "ID错误";
      errItem.style.display = "";
    }

	//初步验证结束，向server端发送信息
    var message = "";
	message += "id=" + id;
    message += "&pass=" + password;
    view_send_request("viewServlet",message);
  }

  function errBack()
  {
    var viewItem = document.getElementById("view");
    var errItem = document.getElementById("err");

    viewItem.style.display = "";
    errItem.style.display = "none";
  }