3回答

• 

  勇恒的思念

  2015-10-04 12:11:34

  /**

  *设置带有过期时间的localStorage

  *@key，localStorage的关键字

  *@v,localStorage的key的值

  *@exp,localStorage过期时间，单位毫秒

  */

  function set(key, v, exp){

  var curTime = new Date().getTime();

  try{

  localStorage.setItem( key, JSON.stringify({data:v, curtime:curTime, exp:exp}) );

  }

  catch(e){

  console.log("set localStorage failed:"+e);

  }

  }

  /**

  *获取带有过期时间的localStorage的值

  *@key，localStorage的关键字

  */

  function get(key){

  try{

  var data = localStorage.getItem(key);

  }

  catch(e){

  console.log("get localStorage failed:"+e);

  }

  var dataObj = JSON.parse(data);

  if(new Date().getTime() - dataObj.curtime > dataObj.exp){

  console.log("expires:timeout");

  }

  else{

  console.log("data="+dataObj.data);

  }

  }

  set('good', 'luck', 5000);

  get('good');

  
  

  0 1
• 

  勇恒的思念

  2015-10-04 12:11:13

  这是我的，不过将js重新放在了别的目录下，所以你要用的话，改下目录

  0 0
• 

  勇恒的思念

  2015-10-04 12:10:00

  /**

  *将图片以canvas的形式保存在localstorage中

  *@key 图片名称

  *@src 图片相对地址

  */

  function setImg(key, src){

  var img = document.createElement('img');

  //图片加载完成时触发回调函数

  img.addEventListener('load', function(){

  var imgCanvas = document.createElement('canvas'),

  imgContext = imgCanvas.getContext('2d');

  imgCanvas.width = this.width;

  imgCanvas.height = this.height;

  
  

  //渲染图片到canvas中

  imgContext.drawImage(this, 0, 0, this.width, this.height);

  
  

  //用data url的形式取出

  var imgAsDataURL = imgCanvas.toDataURL('image/png');

  
  

  //保存到本地存储中

  try{

  localStorage.setItem(key, imgAsDataURL);

  }

  catch(e){

  console.log("storage failed:" + e);

  }

  }, false);

  }

  /**

  *从本地取得图片

  */

  function getImg(key){

  var srcStr = localStorage.getItem(key);

  var imgObj = document.createElement('img');

  imgObj.src = srcStr;

  document.body.appendChild(imgObj);

  }

  
  

  setImg('img1', 'src/img/doll.jpg');

  getImg('img1');

  
  

  0 1