Some experiments with web applications
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  1. // server url
  2. var serverUrl = "http://widgets.vvo-online.de/abfahrtsmonitor/";
  3. // xmlhttp object function
  4. function getHTTPObject() {
  5. console.log("xml http object function");
  6. var xhr;
  7. if(window.XMLHttpRequest) {
  8. xhr = new XMLHttpRequest();
  9. } else if(window.ActiveXObject) {
  10. xhr = new ActiveXObject("Msxml2.XMLHTTP");
  11. }
  12. return xhr;
  13. }
  14. // ajax call function
  15. function ajaxCall(dataUrl, outputElement, callback) {
  16. console.log("ajax function");
  17. // get the xmlhttp object which is supported
  18. var request = getHTTPObject();
  19. outputElement.innerHTML = "Lade Daten ...";
  20. request.onreadystatechange = function() {
  21. if(request.readyState === 4 && request.status === 200) {
  22. //save ajax response
  23. var response = request.responseText;
  24. // check if callback is a function
  25. if(typeof callback === "function") {
  26. callback(response);
  27. }
  28. }
  29. };
  30. request.open("get", dataUrl, true);
  31. request.send(null);
  32. }
  33. // wrap all in anonymous function to get out of global scope
  34. (function() {
  35. console.log("anonymous function");
  36. // get the search form
  37. var searchForm = document.getElementById("search-form");
  38. // haltestelle object
  39. var haltestelle = {
  40. getInfo : function(event) {
  41. console.log("getInfo function");
  42. // prevent submit default behaviour
  43. event.preventDefault();
  44. // get output area
  45. var target = document.getElementById("output");
  46. var hstName = document.getElementById("q").value;
  47. var hstUrl = serverUrl + "Abfahrten.do?ort=dresden&hst=" + hstName;
  48. ajaxCall(hstUrl, target, function(data) {
  49. target.innerHTML = "";
  50. target.innerHTML = "<p>" + data + "</p>";
  51. });
  52. }
  53. };
  54. //event listeners
  55. searchForm.addEventListener("submit", haltestelle.getInfo, false);
  56. })(); // end of anonymous function