基于纯 JS 的简单 localStorage polyfill:
演示:http://jsfiddle.net/aamir/S4X35/
网页:
<a href='#' onclick="store.set('foo','bar')">set key: foo, with value: bar</a><br/>
<a href='#' onclick="alert(store.get('foo'))">get key: foo</a><br/>
<a href='#' onclick="store.del('foo')">delete key: foo</a>
JS:
window.store = {
localStoreSupport: function() {
try {
return 'localStorage' in window && window['localStorage'] !== null;
} catch (e) {
return false;
}
},
set: function(name,value,days) {
if (days) {
var date = new Date();
date.setTime(date.getTime()+(days*24*60*60*1000));
var expires = "; expires="+date.toGMTString();
}
else {
var expires = "";
}
if( this.localStoreSupport() ) {
localStorage.setItem(name, value);
}
else {
document.cookie = name+"="+value+expires+"; path=/";
}
},
get: function(name) {
if( this.localStoreSupport() ) {
var ret = localStorage.getItem(name);
//console.log(typeof ret);
switch (ret) {
case 'true':
return true;
case 'false':
return false;
default:
return ret;
}
}
else {
// cookie fallback
/*
* after adding a cookie like
* >> document.cookie = "bar=test; expires=Thu, 14 Jun 2018 13:05:38 GMT; path=/"
* the value of document.cookie may look like
* >> "foo=value; bar=test"
*/
var nameEQ = name + "="; // what we are looking for
var ca = document.cookie.split(';'); // split into separate cookies
for(var i=0;i < ca.length;i++) {
var c = ca[i]; // the current cookie
while (c.charAt(0)==' ') c = c.substring(1,c.length); // remove leading spaces
if (c.indexOf(nameEQ) == 0) { // if it is the searched cookie
var ret = c.substring(nameEQ.length,c.length);
// making "true" and "false" a boolean again.
switch (ret) {
case 'true':
return true;
case 'false':
return false;
default:
return ret;
}
}
}
return null; // no cookie found
}
},
del: function(name) {
if( this.localStoreSupport() ) {
localStorage.removeItem(name);
}
else {
this.set(name,"",-1);
}
}
}