| 1 | // For osh-to-oil.html.
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| 2 |
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| 3 | 'use strict';
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| 4 |
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| 5 | // Append a message to an element. Used for errors.
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| 6 | function appendMessage(elem, msg) {
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| 7 | elem.innerHTML += msg + '<br />';
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| 8 | }
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| 9 |
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| 10 | // jQuery-like AJAX helper, but simpler.
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| 11 |
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| 12 | // Requires an element with id "status" to show errors.
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| 13 | //
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| 14 | // Args:
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| 15 | // errElem: optional element to append error messages to. If null, then
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| 16 | // alert() on error.
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| 17 | // success: callback that is passed the xhr object.
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| 18 | function ajaxGet(url, errElem, success) {
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| 19 | var xhr = new XMLHttpRequest();
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| 20 | xhr.open('GET', url, true /*async*/);
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| 21 | xhr.onreadystatechange = function() {
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| 22 | if (xhr.readyState != 4 /*DONE*/) {
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| 23 | return;
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| 24 | }
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| 25 |
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| 26 | if (xhr.status != 200) {
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| 27 | var msg = 'ERROR requesting ' + url + ': ' + xhr.status + ' ' +
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| 28 | xhr.statusText;
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| 29 | if (errElem) {
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| 30 | appendMessage(errElem, msg);
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| 31 | } else {
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| 32 | alert(msg);
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| 33 | }
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| 34 | return;
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| 35 | }
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| 36 |
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| 37 | success(xhr);
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| 38 | };
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| 39 | xhr.send();
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| 40 | }
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| 41 |
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| 42 | // Fill in title and iframe src attributes.
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| 43 | function loadSource(sourceName, statusElem) {
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| 44 | document.getElementById('title').innerHTML = sourceName;
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| 45 |
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| 46 | document.getElementById('orig').src = sourceName + '.txt';
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| 47 | document.getElementById('oil').src = sourceName + '__oil.txt';
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| 48 | document.getElementById('ast').src = sourceName + '__ast.html';
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| 49 |
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| 50 | document.getElementById('link-orig').href = sourceName + '.txt';
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| 51 | document.getElementById('link-oil').href = sourceName + '__oil.txt';
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| 52 | document.getElementById('link-ast').href = sourceName + '__ast.html';
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| 53 |
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| 54 | // NOTE: There is no error checking here. They will just see a 404 in the
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| 55 | // iframe pane.
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| 56 | // http://stackoverflow.com/questions/16499117/how-to-detect-an-error-404-in-an-iframe
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| 57 | //appendMessage(statusElem, "Loaded contents for " + sourceName);
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| 58 | }
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| 59 |
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| 60 | function getNameFromHash(urlHash, statusElem) {
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| 61 | var h = urlHash.substring(1); // without leading #
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| 62 | if (h.length < 1) {
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| 63 | appendMessage(statusElem, "Invalid URL hash: [" + urlHash + "]");
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| 64 | return null;
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| 65 | }
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| 66 | return h;
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| 67 | }
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| 68 |
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| 69 | function onLoad(urlHash, globals, statusElem) {
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| 70 | onHashChange(urlHash, globals, statusElem);
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| 71 | }
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| 72 |
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| 73 | // This is the onhashchange handler.
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| 74 | function onHashChange(urlHash, globals, statusElem) {
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| 75 | var sourceName = getNameFromHash(urlHash, statusElem);
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| 76 | if (sourceName === null) return;
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| 77 |
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| 78 | loadSource(sourceName, statusElem)
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| 79 | }
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