84 lines
2.1 KiB
JavaScript
84 lines
2.1 KiB
JavaScript
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/**
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* Returns an XMLHttp instance to use for asynchronous
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* downloading. This method will never throw an exception, but will
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* return NULL if the browser does not support XmlHttp for any reason.
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* @return {XMLHttpRequest|Null}
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*/
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function createXmlHttpRequest() {
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try {
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if (typeof ActiveXObject != 'undefined') {
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return new ActiveXObject('Microsoft.XMLHTTP');
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} else if (window["XMLHttpRequest"]) {
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return new XMLHttpRequest();
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}
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} catch (e) {
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changeStatus(e);
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}
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return null;
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};
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/**
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* This functions wraps XMLHttpRequest open/send function.
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* It lets you specify a URL and will call the callback if
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* it gets a status code of 200.
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* @param {String} url The URL to retrieve
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* @param {Function} callback The function to call once retrieved.
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*/
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function downloadUrl(url, callback) {
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var status = -1;
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var request = createXmlHttpRequest();
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if (!request) {
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return false;
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}
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request.onreadystatechange = function() {
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if (request.readyState == 4) {
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try {
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status = request.status;
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} catch (e) {
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// Usually indicates request timed out in FF.
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}
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if (status == 200) {
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callback(request.responseXML, request.status);
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request.onreadystatechange = function() {};
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}
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}
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}
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request.open('GET', url, true);
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try {
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request.send(null);
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} catch (e) {
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changeStatus(e);
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}
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};
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/**
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* Parses the given XML string and returns the parsed document in a
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* DOM data structure. This function will return an empty DOM node if
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* XML parsing is not supported in this browser.
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* @param {string} str XML string.
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* @return {Element|Document} DOM.
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*/
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function xmlParse(str) {
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if (typeof ActiveXObject != 'undefined' && typeof GetObject != 'undefined') {
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var doc = new ActiveXObject('Microsoft.XMLDOM');
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doc.loadXML(str);
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return doc;
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}
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if (typeof DOMParser != 'undefined') {
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return (new DOMParser()).parseFromString(str, 'text/xml');
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}
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return createElement('div', null);
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}
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/**
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* Appends a JavaScript file to the page.
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* @param {string} url
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*/
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function downloadScript(url) {
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var script = document.createElement('script');
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script.src = url;
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document.body.appendChild(script);
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}
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