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Chrome中新javascript api: websockets與webdatabase的用法
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发表于: 2013-6-26 16:10 1156
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隨便記錄一些新的javascript寫法,只在新發布的chrome4.0穩定版中可以使用的:
Web Sockets API:
if ("WebSocket" in window) {
var ws = new WebSocket("ws://example.com/service");
ws.onopen = function() {
// Web Socket is connected. You can send data by send() method.
ws.send("message to send"); ....
};
ws.onmessage = function (evt) { var received_msg = evt.data; ... };
ws.onclose = function() { // websocket is closed. };
} else {
// the browser doesn't support WebSocket.
}
ws://是一個新的標簽,其用法和http基本一樣。也可以ws://www.a.com:8888/aa
webdatabase:
var database = openDatabase("Database Name", "Database Version");
database.executeSql("SELECT * FROM test", function(result1) {
// do something with the results
database.executeSql("DROP TABLE test", function(result2) {
// do some more stuff
alert("My second database query finished executing!");
});
});
try {
if (window.openDatabase) {
db = openDatabase("NoteTest", "1.0", "HTML5 Database API example", 200000);
if (!db)
alert("Failed to open the database on disk. This is probably because the version was bad or there is not enough space left in this domain's quota");
} else
alert("Couldn't open the database. Please try with a WebKit nightly with this feature enabled");
} catch(err) { }
db.transaction(function(tx) {
tx.executeSql("SELECT COUNT(*) FROM WebkitStickyNotes", [], function(result) {
loadNotes();
}, function(tx, error) {
tx.executeSql("CREATE TABLE WebKitStickyNotes (id REAL UNIQUE, note TEXT, timestamp REAL, left TEXT, top TEXT, zindex REAL)", [], function(result) {
loadNotes();
});
});
});
webdatabase的實現是通過本地的sqlite數據庫。
Web Sockets API:
if ("WebSocket" in window) {
var ws = new WebSocket("ws://example.com/service");
ws.onopen = function() {
// Web Socket is connected. You can send data by send() method.
ws.send("message to send"); ....
};
ws.onmessage = function (evt) { var received_msg = evt.data; ... };
ws.onclose = function() { // websocket is closed. };
} else {
// the browser doesn't support WebSocket.
}
ws://是一個新的標簽,其用法和http基本一樣。也可以ws://www.a.com:8888/aa
webdatabase:
var database = openDatabase("Database Name", "Database Version");
database.executeSql("SELECT * FROM test", function(result1) {
// do something with the results
database.executeSql("DROP TABLE test", function(result2) {
// do some more stuff
alert("My second database query finished executing!");
});
});
try {
if (window.openDatabase) {
db = openDatabase("NoteTest", "1.0", "HTML5 Database API example", 200000);
if (!db)
alert("Failed to open the database on disk. This is probably because the version was bad or there is not enough space left in this domain's quota");
} else
alert("Couldn't open the database. Please try with a WebKit nightly with this feature enabled");
} catch(err) { }
db.transaction(function(tx) {
tx.executeSql("SELECT COUNT(*) FROM WebkitStickyNotes", [], function(result) {
loadNotes();
}, function(tx, error) {
tx.executeSql("CREATE TABLE WebKitStickyNotes (id REAL UNIQUE, note TEXT, timestamp REAL, left TEXT, top TEXT, zindex REAL)", [], function(result) {
loadNotes();
});
});
});
webdatabase的實現是通過本地的sqlite數據庫。
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