function getCookieVal (offset) {
  var endstr = document.cookie.indexOf (";", offset);
  if (endstr == -1) endstr = document.cookie.length;
  return unescape(document.cookie.substring(offset, endstr));
}

function getCookie (name) {
  var arg = name + "=";
  var alen = arg.length;
  var clen = document.cookie.length;
  var i = 0;
  while (i < clen) {
    var j = i + alen;
    if (document.cookie.substring(i, j) == arg) {
      return getCookieVal (j);
    }
    i = document.cookie.indexOf(" ", i) + 1;
    if (i == 0) {
      break;
    }
  }
  return null;
}

function setCookie (name, value) {
  var exp = new Date();
  exp.setTime(exp.getTime() + 864000000); //一天换算成毫秒：24 * 60 * 60 * 1000 = 864000000
  document.cookie = name + "=" + value + "; expires=" + exp.toGMTString();
}

function history_show(){
  var history_info = getCookie("history_info");
  var content = "";
  if(history_info != null){
    history_arg = history_info.split("--michael.tsai--");
    for(var i=0; i < 30; i++){ //最多显示 30 条历史记录
      if(history_arg[i] != null && history_arg[i] != 'null'){
        var currentHistory = history_arg[i].split("--cai.shuliang--");
        var limit_len = 12;//显示 10 个汉字字符，或 20 个英文字母或数字
        var finalLength = getLength(currentHistory[0], limit_len);
        var displayText = currentHistory[0].substr(0, finalLength);
        if(getLeftChars(currentHistory[0], limit_len) < 0){
          displayText += "...";
        }
        content += ("<a href='"+currentHistory[1]+"' class='lb' title='" + currentHistory[0] + "' target='_blank'>" + displayText + "</a><br>");
      }
      document.getElementById("history").innerHTML = content;
    }
  }
  else{
    document.getElementById("history").innerHTML="目前没有任何浏览纪录";
  }
}

//写入 cookie
function writeCookie(type){
  var title = document.title.split(" | ")[0];
      title = type + "：" + title;
  var href = document.location;
  var currentHistory = title + "--cai.shuliang--" + href + "--michael.tsai--";
  old_info = getCookie("history_info");

  var insert = true;
  if(old_info != null){
    var old_link = old_info.split("--michael.tsai--");
    for(var j=0; j < old_link.length; j++){
      if(old_link[j].indexOf(title) != -1){
        insert = false;
      }
      if(old_link[j] == "null"){
        break;
      }
    }
  }

  if(insert){
    currentHistory += getCookie("history_info");
    setCookie("history_info",currentHistory);
  }

}