Question

我有一个脚本，我需要检查用户名和密码，并使用sqlite事务显示一个消息。状态msg在正确的条目中显示相应的消息，但不会显示错误条目的警报消息。可以解决这个问题。脚本如下：

var db = openDatabase('mydb', '1.0', 'Test DB', 2 * 1024 * 1024);
db.transaction(function (tx) {
tx.executeSql("CREATE TABLE IF NOT EXISTS Contact1(id unique, username TEXT NOT NULL, pass TEXT NOT NULL)");
tx.executeSql("INSERT INTO Contact1(id, username, pass) VALUES (1, 'pp1', '321')");
// tx.executeSql('INSERT INTO LOGS (id, log) VALUES (2, "logmsg")');
});


$(document).ready(function () // Call function when page is ready for load..

{
 db.transaction(function (tx) {
 tx.executeSql("INSERT INTO Contact1(id, username, pass) VALUES (3, 'pp1', '321')"); 
});

$("#sub").click(function(){
var uname = $("#username").val();
var password = $("#password").val();
db.transaction(function (tx) {
tx.executeSql('SELECT * FROM Contact1 WHERE username=?', [uname], function (tx, results) {
 var len = results.rows.length, i;
// msg = "<p>Found rows: " + len + "</p>";
 //document.querySelector('#status').innerHTML +=  msg;
 for (i = 0; i < len; i++){
 //  msg = "<p><b>" + results.rows.item(i).pass + "</b></p>";
 //document.querySelector('#status').innerHTML +=  msg;
 if(results.rows.item(i).username == uname){
// alert("hello");
        tx.executeSql('SELECT * FROM Contact1 WHERE  pass=?', [password], function (tx, results) {
           var len = results.rows.length, i;
           msg = "<p>Found rows: " + len + "</p>";
           document.querySelector('#status').innerHTML +=  msg;
           for (i = 0; i < len; i++){
             msg = "<p><b>" + results.rows.item(i).username + "</b>==><b>" + results.rows.item(i).pass + "</b></p>";
             document.querySelector('#status').innerHTML +=  msg;
           }

         }, null);

         }
 else
  {//wrong username/password case
   msg="<p><b>Please enter the right Username and password"+"</b></p>";
   document.querySelector('#status').innerHTML +=  msg;
  }
 }
}, null);

});});});

提前致谢：D

Answer 1

根据您的代码
如果用户名是错误的，则返回len = 0，因此它不会进入else条件。试试这个

$("#sub").click(function(){
var uname = $("#username").val();
var password = $("#password").val();
db.transaction(function (tx) {
tx.executeSql('SELECT * FROM Contact1 ', function (tx, results) {
var len = results.rows.length, i;
for (i = 0; i < len; i++){
if(results.rows.item(i).username == uname &&results.rows.item(i).pass == password){
// alert("hello");
          msg = "<p><b>" + results.rows.item(i).username + "</b>==><b>" + results.rows.item(i).pass +      "</b></p>";
         document.querySelector('#status').innerHTML +=  msg;
       }
else
{
msg="<p><b>Please enter the right Username and password"+"</b></p>";
document.querySelector('#status').innerHTML +=  msg;
}
}
}, null);

Answer 2

Suganthi指出了问题，但是我决定重写你的代码以解决问题并使代码更好：

var db;

document.addEventListener("deviceready", onDeviceReady, false);

function onDeviceReady() {
    db = openDatabase('mydb', '1.0', 'Test DB', 2 * 1024 * 1024);
    db.transaction(function (tx) {
        tx.executeSql("CREATE TABLE IF NOT EXISTS Contact1(id unique, username TEXT NOT NULL, pass TEXT NOT NULL)");
        tx.executeSql("INSERT INTO Contact1(id, username, pass) VALUES (1, 'pp1', '321')");
        tx.executeSql("INSERT INTO Contact1(id, username, pass) VALUES (3, 'pp1', '321')"); 
    });
}

$("#sub").click(function() {
    var uname = $("#username").val();
    var password = $("#password").val();
    db.transaction(function (tx) {
        tx.executeSql('SELECT * FROM Contact1 WHERE username = ? AND pass = ?', [uname, password], function (tx, results) {
            var len = results.rows.length;
            if (len > 0) {
                $('#status').append("<p>Found rows: " + len + "</p>");
                for (i = 0; i < len; i++) {
                    msg = "<p><b>" + results.rows.item(i).username + "</b>==><b>" + results.rows.item(i).pass + "</b></p>";
                    $('#status').append(msg);
                }
            } else {
                msg = "<p><b>Please enter correct username and password</b></p>";
                $('#status').append(msg);
            }
        }, null);
    });
});

脚本中的其他条件与sqlite

2 个答案: