85 lines
2.4 KiB
JavaScript
85 lines
2.4 KiB
JavaScript
// jXHR.js (JSON-P XHR)
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// v0.1 (c) Kyle Simpson
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// MIT License
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(function(global){
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var SETTIMEOUT = global.setTimeout, // for better compression
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doc = global.document,
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callback_counter = 0;
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global.jXHR = function() {
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var script_url,
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script_loaded,
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jsonp_callback,
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scriptElem,
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publicAPI = null;
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function removeScript() { try { scriptElem.parentNode.removeChild(scriptElem); } catch (err) { } }
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function reset() {
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script_loaded = false;
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script_url = "";
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removeScript();
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scriptElem = null;
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fireReadyStateChange(0);
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}
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function ThrowError(msg) {
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try { publicAPI.onerror.call(publicAPI,msg,script_url); } catch (err) { throw new Error(msg); }
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}
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function handleScriptLoad() {
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if ((this.readyState && this.readyState!=="complete" && this.readyState!=="loaded") || script_loaded) { return; }
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this.onload = this.onreadystatechange = null; // prevent memory leak
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script_loaded = true;
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if (publicAPI.readyState !== 4) ThrowError("Script failed to load ["+script_url+"].");
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removeScript();
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}
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function fireReadyStateChange(rs,args) {
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args = args || [];
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publicAPI.readyState = rs;
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if (typeof publicAPI.onreadystatechange === "function") publicAPI.onreadystatechange.apply(publicAPI,args);
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}
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publicAPI = {
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onerror:null,
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onreadystatechange:null,
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readyState:0,
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open:function(method,url){
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reset();
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internal_callback = "cb"+(callback_counter++);
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(function(icb){
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global.jXHR[icb] = function() {
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try { fireReadyStateChange.call(publicAPI,4,arguments); }
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catch(err) {
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publicAPI.readyState = -1;
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ThrowError("Script failed to run ["+script_url+"].");
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}
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global.jXHR[icb] = null;
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};
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})(internal_callback);
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script_url = url.replace(/=\?/,"=jXHR."+internal_callback);
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fireReadyStateChange(1);
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},
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send:function(){
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SETTIMEOUT(function(){
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scriptElem = doc.createElement("script");
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scriptElem.setAttribute("type","text/javascript");
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scriptElem.onload = scriptElem.onreadystatechange = function(){handleScriptLoad.call(scriptElem);};
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scriptElem.setAttribute("src",script_url);
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doc.getElementsByTagName("head")[0].appendChild(scriptElem);
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},0);
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fireReadyStateChange(2);
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},
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setRequestHeader:function(){}, // noop
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getResponseHeader:function(){return "";}, // basically noop
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getAllResponseHeaders:function(){return [];} // ditto
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};
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reset();
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return publicAPI;
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};
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})(window);
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