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分享html5中localStorage的实例教程

使用html5的storage来保存数据. 做了个小工具来用一下这个新特性。

需求说明: 有时发现有好的英语表达或者是陌生的单词,总是想记下来,但是过几天之后又不记得了,更别说运用了.

<!DOCTYPE html>  <head>  <meta charset="UTF-8">  <title>SO EASY!</title>  <style type="text/css">      html,body {    background-color: #262;          color: #fff;          font-family: helvetica, arial, sans-serif;          margin: 0;          padding: 0;          font-size: 11pt;      }         </style>  <script lang='text/javascript'>     window.addEventListener("load", eventWindowLoaded, false);     var entries = [];     var curIndex = -1;     function eventWindowLoaded()     {         loadEntries(1);         showNext();         var dayselection = $("dayselection");         dayselection.addEventListener("change", daysSelectionChanged, false);        }   function daysSelectionChanged(e)      {          var target = e.target;          loadEntries(target.value);            clearTextarea();          curIndex = -1;          showNext();          log('总共'+entries.length+'个, 当前第'+(curIndex+1)+'个');      }       function loadEntries(days)      {          var now = new Date().getTime();          var arr = [];          for(var i=0; i<localStorage.length; i++)          {              var time = localStorage.key(i);              var daysBetween = (now - time)/24/60/60/1000;              // console.log(daysBetween);              if (daysBetween <= days)              {                  var value = JSON.parse(localStorage.getItem(time));                  var entry = {time: time, data: value};                  arr.push(entry);              }          }          entries = arr;      }        function saveEntry()      {          var data_en = $('en').value;          var data_zh = $('zh').value;          var data = {en: data_en, zh: data_zh};          var time = new Date().getTime();          if (data_en =='' && data_zh == '') // TODO: 正则          {              alert('必须输入中英文表达!');          }          else          {              localStorage.setItem(time, JSON.stringify(data));                             // Update UI              log('保存成功!');              // ReLoad entries              loadEntries($('dayselection').value);              // Recovery current entry              curIndex --;              showNext();          }      }       function deleteEntry()      {          var currentEntry = entries[curIndex];          if (currentEntry)          {              localStorage.removeItem(currentEntry.time);              // Update UI              log('删除成功!');              // Reload entries              loadEntries($('dayselection').value);              // Go to next entry              curIndex --;              showNext();          }      }        function clearStorage()      {          localStorage.clear();          log('数据初始化完成!');      }        function showNext()      {             if (curIndex +1 <= entries.length-1)          {              curIndex ++;              var entry = entries[curIndex];              showTextarea(entry.data);                log('总共'+entries.length+'个, 当前第'+(curIndex+1)+'个');          }      }        function showPrevious()      {          if (curIndex-1 >= 0)          {              curIndex --;              var entry = entries[curIndex];                        showTextarea(entry.data);                log('总共'+entries.length+'个, 当前第'+(curIndex+1)+'个');          }      }        function showTextarea(data)      {          var target_en = $('en');          var target_zh = $('zh');          target_en.value = data.en;          target_zh.value = data.zh;      }        function clearTextarea()      {          $('en').value = '';          $('zh').value = '';      }        function $(id)      {          return document.getElementById(id);      }        function log(msg)      {          var target = document.getElementById('msg');          target.innerHTML = msg;      }      </script>  </head>  <body>  <div style="position: absolute; top: 50px; left: 50px;">      回顾:<select id="dayselection">        <option value="1"> 1天内 </option>        <option value="0.04166666667"> 1小时内 </option>        <option value="3"> 3天内 </option>        <option value="7"> 7天内 </option>        <option value="14"> 14天内 </option>        <option value="30"> 1月内 </option>        <!-- <option value="">  </option> -->      </select>      </tr>      <input type="button" id="prev" value="上一个" onclick="showPrevious();">      <input type="button" id="next" value="下一个" onclick="showNext();">      <hr> 英语表达:<br/>      <textarea id="en" cols="40" rows="6"></textarea>      <hr> 中文解释:<br/>      <textarea id="zh" cols="40" rows="6"></textarea><br/>      <input type="button" id="save" value="保存内容" onclick="saveEntry();">      <input type="button" id="delete" value="删除内容" onclick="deleteEntry();">           <hr> <p id="msg"></p>    <div>  </body>  </html>

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