html5 Database Storage

//创建数据库
var db = openDatabase("users", "1.0", "用户表", 1024 * 1024); 
if(!db){
    alert("Failed to connect to database."); 
} else {
    alert("connect to database 'K'."); 
}

// 创建表
db.transaction( function(tx) { 
    tx.executeSql(
        "CREATE TABLE IF NOT EXISTS users (id REAL UNIQUE, name TEXT)", 
        [], 
        function(){ alert('创建users表成功'); }, 
        function(tx, error){ alert('创建users表失败:' + error.message); }
    );
}); 

// 插入数据
db.transaction(function(tx) { 
    tx.executeSql(
        "INSERT INTO users (id, name) values(?, ?)", 
        [Math.random(), 'space'], 
        function(){ alert('插入数据成功'); }, 
        function(tx, error){ alert('插入数据失败: ' + error.message);}
    ); 
}); 

// 查询
db.transaction( function(tx) { 
    tx.executeSql(
        "SELECT * FROM users", [],  
         function(tx, result) {
            var rows = result.rows, length = rows.length, i=0;
            for(i; i < length; i++) { 
                alert(
                    'id=' + rows.item(i)['id'] + 
                    'name='+ rows.item(i)['name']
                ); 
            } 
        }, 
        function(tx, error){
            alert('Select Failed: ' + error.message);
        }
    ); 
}); 

// 删除表
db.transaction(function (tx) {  
    tx.executeSql('DROP TABLE users'); 
});