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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<script>
var src = ‘../img/99.jpg‘;
function setImg(key) {
var img = document.createElement(‘img‘);
//当图片加载完成的时候触发回调函数
img.addEventListener(‘load‘, function() {
var imgCanvas = document.createElement(‘canvas‘),
imgContext = imgCanvas.getContext(‘2d‘);
//确保canvas的大小和图片一致
imgCanvas.width = this.width;
imgCanvas.height = this.height;
//渲染图片到canvas中
imgContext.drawImage(this, 0, 0, imgCanvas.width, imgCanvas.height);
//用data——url的形式取出
var imgAsDataUrl = imgCanvas.toDataURL(‘img/png‘);
try {
localStorage.setItem(key, imgAsDataUrl);
} catch (e) {
//TODO handle the exception
console.log("Storage failed" + e);
}
}, false);
img.src = src;
}
function getImg(key) {
var imngSrc = localStorage.getItem(key);
var imgObj = document.createElement(‘img‘);
imgObj.src = imngSrc;
document.body.appendChild(imgObj);
}
</script>
<script>
function set(key, val) {
var currentTime = new Date().getTime();
localStorage.setItem(key, JSON.stringify({
data: val,
time: currentTime
}));
}
function get(key, exp) {
var data=localStorage.getItem(key),
dataObj=JSON.parse(data);
if (new Date().getTime()-data.time>exp) {
console.log(‘‘);
} else{
console.log("data="+dataObj);
}
}
</script>
<script>
var indexDb=window.indexDb||window.webkitIndexedDB;
</script>
</body>
</html>
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原文地址：http://www.cnblogs.com/alphafly/p/4783819.html
