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[英]onClick / onclick does not seem to be working as expected in HTML5 / JavaScript
[英]HTML5/JavaScript/PhoneGap onclick does not function as expected
正在按照本教程讲解如何在PhoneGap / Cordova中使用SQLite。 我复制粘贴了代码并固定了间距,但是,在花了很多时间尝试使其生效之后,我仍然很困惑。
起初我以为sql语句有一个或两个错误,这就是为什么我没有得到任何结果的原因。 但是,进一步检查后,当按下某些按钮的onclick
方法时,即使是简单的警报语句也没有执行。 Body的onload
方法也未执行。
这是我的HTML文件:
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-type" name="viewport" content="width=default-width; user-scalable=no" />
<title>Embedded Sql Example</title>
<!-- include the next line to use phonegap javascript functions -->
<script type="text/javascript" charset="utf-8" src="js/phonegap.js"></script>
<!-- include the next line to use jquery functions in your application
you must download this and include the directory your html file is in
-->
<script type="text/javascript" charset="utf-8" src="js/jquery.min.js"></script>
<!-- main scripts used in this example -->
<script type="text/javascript" charset="utf-8" src="js/gitScript.js"></script>
</head>
<body onload="onBodyLoad();">
<h1>WebSQL</h1>
<input id="txFirstName" type="text" placeholder="FirstName">
<input id="txLastName" type="text" placeholder="Last Name">
<input type="button" value="Add record" onclick="AddValueToDB();">
<input type="button" value="Refresh" onclick="ListDBValues();">
<br><br>
<span style="font-weight:bold;">Currently stored values:</span>
<span id="lbUsers"></span>
</body>
</html>
我有一个名为js
的文件夹,其中包含我使用的所有JavaScript文件。 这是gitScript.js文件:
// global variables
var db;
var shortName = "WebSqlDB";
var version = "1.0";
var displayName = "WebSqlDB";
var maxSize = 65535;
// this is called when an error happens in a transaction
function errorHandler(transaction, error) {
alert("Error: " + error.message + " code: " + error.code);
}
// this is called when a successful transaction happens
function successCallBack() {
alert("DEBUGGING: success");
}
function nullHandler(){};
// called when the application loads
function onBodyLoad(){
// This alert is used to make sure the application is loaded correctly
// you can comment this out once you have the application working
alert("DEBUGGING: we are in the onBodyLoad() function");
if (!window.openDatabase) {
// not all mobile devices support databases if it does not, the
// following alert will display
// indicating the device will not be albe to run this application
alert("Databases are not supported in this browser.");
return;
}
// this line tries to open the database base locally on the device
// if it does not exist, it will create it and return a database
// object stored in variable db
db = openDatabase(shortName, version, displayName,maxSize);
// this line will try to create the table User in the database just created/openned
db.transaction(function(tx){
tx.executeSql( "CREATE TABLE IF NOT EXISTS User(UserId INTEGER NOT NULL PRIMARY KEY, FirstName TEXT NOT NULL, LastName TEXT NOT NULL)", [],nullHandler,errorHandler);
},errorHandler,successCallBack);
}
// list the values in the database to the screen using jquery to
// update the #lbUsers element
function ListDBValues() {
if (!window.openDatabase) {
alert("Databases are not supported in this browser.");
return;
}
// this line clears out any content in the #lbUsers element on the
// page so that the next few lines will show updated
// content and not just keep repeating lines
$('#lbUsers').html('');
// this next section will select all the content from the User table
// and then go through it row by row
// appending the UserId FirstName LastName to the #lbUsers element
// on the page
db.transaction(function(transaction) {
transaction.executeSql("SELECT * FROM User;", [],
function(transaction, result) {
if (result != null && result.rows != null) {
for (var i = 0; i < result.rows.length; i++) {
var row = result.rows.item(i);
$('#lbUsers').append('<br>' + row.UserId + '. ' + row.FirstName+ ' ' + row.LastName);
}
}
},errorHandler);
},errorHandler,nullHandler);
return;
}
// this is the function that puts values into the database using the
// values from the text boxes on the screen
function AddValueToDB() {
alert("Add Value to DB entered");
if (!window.openDatabase) {
alert("Databases are not supported in this browser.");
return;
}
// this is the section that actually inserts the values into the User table
db.transaction(function(transaction) {
transaction.executeSql('INSERT INTO User(FirstName, LastName)
VALUES (?,?)',[$('#txFirstName').val(), $('#txLastName').val()],
nullHandler,errorHandler);
});
db.transaction(function(transaction) {
transaction.executeSql('INSERT INTO User(FirstName, LastName)
VALUES (?,?)',["FirstName", "LastName"],
nullHandler,errorHandler);
});
// this calls the function that will show what is in the User table in the database
ListDBValues();
return false;
}
我真的不知道这是怎么回事。 我已经用另一个SQLite PhoneGap教程仔细检查了它,而且很难看到上面的代码哪里出错了。
我有一种基本的感觉,自从我不得不使用JavaScript和我第一次使用HTML5以来已有很长时间了。
问题是JavaScript文件中有错误。 我通过链接另一个JavaScript文件解决了这个问题,而html文件可以很好地看到第二个JavaScript文件中的功能。 我使用了Chrome调试器来找出错误所在的位置,以及这些错误完全是另一个问题。
另外,似乎使用phonegap.js和cordova.js之间没有区别。
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