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<html>

<head>

</head>

<body>

/* AjaxHandler interface. */

// var AjaxHandler = new Interface('AjaxHandler', ['request', 'createXhrObject']);

/* SimpleHandler class. */

var SimpleHandler = function() {}; // implements AjaxHandler

SimpleHandler.prototype = {

request: function(method, url, callback, postVars) {

var xhr = this.createXhrObject();

xhr.onreadystatechange = function() {

if(xhr.readyState !== 4) return;

(xhr.status === 200) ?

callback.success(xhr.responseText, xhr.responseXML) :

callback.failure(xhr.status);

};

xhr.open(method, url, true);

if(method !== 'POST') postVars = null;

xhr.send(postVars);

createXhrObject: function() { // Factory method.

var methods = [

function() { return new XMLHttpRequest(); },

function() { return new ActiveXObject('Msxml2.XMLHTTP'); },

function() { return new ActiveXObject('Microsoft.XMLHTTP'); }

];

for(var i = 0, len = methods.length; i < len; i++) {

try {

methods[i]();

}

catch(e) {

continue;

}

// If we reach this point, method[i] worked.

this.createXhrObject = methods[i]; // Memoize the method. 记住该方法

return methods[i]();

}

// If we reach this point, none of the methods worked.

throw new Error('SimpleHandler: Could not create an XHR object.');

}

};

/* Usage. */

var myHandler = new SimpleHandler();

var callback = {

success: function(responseText) { alert('Success: ' + responseText); },

failure: function(statusCode) { alert('Failure: ' + statusCode); }

};

myHandler.request('GET', 'script.php', callback);

</script>

</body>

</html>

javascript-code/index.html at master · hchenc/javascript-code · GitHub

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