Ajax Programming :: What's wrong with this rookie code?


	What's wrong with this rookie code? Hi there -- I've been trying to get a basic XMLHttpRequest object to read in XML from an XML file and it's not working. I'm sure there's something really simple I'm just overlooking. I've been comparing it to code I found on the web that definitely works and can't figure out what the difference is aside from try catch statements (maybe that's it?). Anyway, this is the code. Basically, I'm just trying to get an acknowledgment that it actually read in XML from the file but Firefox says the xmlDoc object is null... and while IE recognizes the object, any processing I do on it fails. Thanks for any help! function addMovies() { var req = null; if (window.XMLHttpRequest) { req = new XMLHttpRequest(); } else { if (window.ActiveXObject) { req = new ActiveXObject("Microsoft.XMLHTTP"); } } req.onreadystatechange = function() { if (req.readyState == 4) { if (req.status == 200) { var xmlDoc = req.responseXML; window.alert(xmlDoc); document.getElementById("theClicker").disabled = true; } else if (req.status == 404) { window.alert("The requested URL does not exist!"); } else { window.alert("Error: status code = " + req.status); } } }; req.open("GET", "ajaxtest.xml", true); req.setRequestHeader("Content-Type", "text/xml"); req.send(null); } Read this: http://radio.javaranch.com/pascarello/2006/09/12/1158096122600.html Eric On 11/17/06, The alMIGHTY N <natle@yahoo.com> wrote: - Hide quoted text - > Hi there -- I've been trying to get a basic XMLHttpRequest object to > read in XML from an XML file and it's not working. I'm sure there's > something really simple I'm just overlooking. I've been comparing it to > code I found on the web that definitely works and can't figure out what > the difference is aside from try catch statements (maybe that's it?). > Anyway, this is the code. Basically, I'm just trying to get an > acknowledgment that it actually read in XML from the file but Firefox > says the xmlDoc object is null... and while IE recognizes the object, > any processing I do on it fails. > Thanks for any help! > function addMovies() { > var req = null; > if (window.XMLHttpRequest) { > req = new XMLHttpRequest(); > } else { > if (window.ActiveXObject) { > req = new ActiveXObject(" > Microsoft.XMLHTTP"); > } > } > req.onreadystatechange = function() { > if (req.readyState == 4) { > if (req.status == 200) { > var xmlDoc = > req.responseXML; > window.alert(xmlDoc); > document.getElementById("theClicker").disabled > = true; > } else if (req.status == 404) { > window.alert("The requested > URL does not exist!"); > } else { > window.alert("Error: status > code = " + req.status); > } > } > }; > req.open("GET", "ajaxtest.xml", true); > req.setRequestHeader("Content-Type", "text/xml"); > req.send(null); > } Hi Eric, Thanks for the response! I visited the URL you posted but still cannot figure out what the problem is. Please forgive my ignorance: a) Did you set your content type to text/xml? I think so. Isn't that what the line "req.setRequestHeader("Content-Type", "text/xml");" is supposed to do? Do I need to somehow do this in the actual XML file itself? b) Is your request actually making it to the server and back? I tested out the script with some window alerts for the status - the correct status code of 200 is going through... c) When you alert/examine the responseText, do you see anything that does not belong? I'm opening a static XML file that I checked for syntax using Internet Explorer. I think that should cover this point... or am I missing something? d) Open up the dynamic XML document in your browser directly. (Type the url into the browser. This may require you to hard code post parameters or build a test form.) The browser will tell you if your XML is not formatted correctly. Is it formatted correctly? See the answer to c. :-D This is really confusing me. Is it possible that perhaps the server is not set up to serve up XML documents? Is there some sort of special setting in Weblogic that enables delivery of XML documents? It's really strange... Even though I'm explicitly opening an XML file and the content-type is being set to text/xml (as far as I know), the response headers keep coming back with a content-type of text/plain. Should this tell me something? Thanks! NL - Hide quoted text - Eric Pascarello wrote: > Read this: > http://radio.javaranch.com/pascarello/2006/09/12/1158096122600.html > Eric > On 11/17/06, The alMIGHTY N <natle@yahoo.com> wrote: > > Hi there -- I've been trying to get a basic XMLHttpRequest object to > > read in XML from an XML file and it's not working. I'm sure there's > > something really simple I'm just overlooking. I've been comparing it to > > code I found on the web that definitely works and can't figure out what > > the difference is aside from try catch statements (maybe that's it?). > > Anyway, this is the code. Basically, I'm just trying to get an > > acknowledgment that it actually read in XML from the file but Firefox > > says the xmlDoc object is null... and while IE recognizes the object, > > any processing I do on it fails. > > Thanks for any help! > > function addMovies() { > > var req = null; > > if (window.XMLHttpRequest) { > > req = new XMLHttpRequest(); > > } else { > > if (window.ActiveXObject) { > > req = new ActiveXObject(" > > Microsoft.XMLHTTP"); > > } > > } > > req.onreadystatechange = function() { > > if (req.readyState == 4) { > > if (req.status == 200) { > > var xmlDoc = > > req.responseXML; > > window.alert(xmlDoc); > > document.getElementById("theClicker").disabled > > = true; > > } else if (req.status == 404) { > > window.alert("The requested > > URL does not exist!"); > > } else { > > window.alert("Error: status > > code = " + req.status); > > } > > } > > }; > > req.open("GET", "ajaxtest.xml", true); > > req.setRequestHeader("Content-Type", "text/xml"); > > req.send(null); > > } > ------=_Part_91268_366310.1163801434935 > Content-Type: text/html; charset=ISO-8859-1 > Content-Transfer-Encoding: quoted-printable > X-Google-AttachSize: 6859 > <div>Read this:</div> > <div></div> > <div><a href=3D"http://radio.javaranch.com/pascarello/2006/09/12/1158096122600.html">http://radio.javaranch.com/pascarello/2006/09/12/1158096122600.html</a></div> > <div></div> > <div>Eric<br><br></div> > <div><span class=3D"gmail_quote">On 11/17/06, <b class=3D"gmail_sendername">The alMIGHTY N</b> <<a href=3D"mailto:natle@yahoo.com">natle@yahoo.com</a>> wrote:</span> > <blockquote class=3D"gmail_quote" style=3D"PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"><br>Hi there -- I've been trying to get a basic XMLHttpRequest object to<br>read in XML from an XML file and it's not working. I'm sure there's > <br>something really simple I'm just overlooking. I've been comparing it to<br>code I found on the web that definitely works and can't figure out what<br>the difference is aside from try catch statements (maybe that's it?). > <br><br>Anyway, this is the code. Basically, I'm just trying to get an<br>acknowledgment that it actually read in XML from the file but Firefox<br>says the xmlDoc object is null... and while IE recognizes the object,<br>any processing I do on it fails. > <br><br>Thanks for any help!<br><br> function addMovies() {<br> var req =3D null;<br> if (window.XMLHttpRequest) {<br> req =3D new XMLHttpRequest(); > <br> } else {<br> if (window.ActiveXObject) {<br> req =3D new ActiveXObject("Microsoft.XMLHTTP");<br> } > <br> }<br> req.onreadystatechange =3D function() {<br> if (req.readyState =3D=3D 4) {<br> if (req.status =3D=3D 200) {<br> > var xmlDoc =3D req.responseXML;<br> window.alert(xmlDoc);<br> document.getElementById > ("theClicker").disabled =3D true;<br> } else if (req.status =3D=3D 404) {<br> window.alert("The requested URL does not exist!"); > <br> } else {<br> window.alert("Error: status code =3D " + req.status);<br> }<br> } > <br> };<br> req.open("GET", "ajaxtest.xml", true);<br> req.setRequestHeader("Content-Type", "text/xml");<br>=20 > req.send(null);<br> }<br><br><br></div><br>=0A > ------=_Part_91268_366310.1163801434935-- It sounds like perhaps the MIME type of the response is not correct. The XML object will be NULL if your response is something such as "text/plain". Make sure your MIME type is either: application/xml or text/xml Hope that helps, -Todd On 11/20/06, The alMIGHTY N <natle@yahoo.com> wrote: - Hide quoted text - > Hi Eric, > Thanks for the response! I visited the URL you posted but still cannot > figure out what the problem is. Please forgive my ignorance: > a) Did you set your content type to text/xml? > I think so. Isn't that what the line > "req.setRequestHeader("Content-Type", "text/xml");" is supposed to do? > Do I need to somehow do this in the actual XML file itself? > b) Is your request actually making it to the server and back? > I tested out the script with some window alerts for the status - the > correct status code of 200 is going through... > c) When you alert/examine the responseText, do you see anything that > does not belong? > I'm opening a static XML file that I checked for syntax using Internet > Explorer. I think that should cover this point... or am I missing > something? > d) Open up the dynamic XML document in your browser directly. (Type the > url into the browser. This may require you to hard code post parameters > or build a test form.) The browser will tell you if your XML is not > formatted correctly. Is it formatted correctly? > See the answer to c. :-D > This is really confusing me. Is it possible that perhaps the server is > not set up to serve up XML documents? Is there some sort of special > setting in Weblogic that enables delivery of XML documents? > It's really strange... Even though I'm explicitly opening an XML file > and the content-type is being set to text/xml (as far as I know), the > response headers keep coming back with a content-type of text/plain. > Should this tell me something? > Thanks! > NL > Eric Pascarello wrote: > > Read this: > > http://radio.javaranch.com/pascarello/2006/09/12/1158096122600.html > > Eric > > On 11/17/06, The alMIGHTY N <natle@yahoo.com> wrote: > > > Hi there -- I've been trying to get a basic XMLHttpRequest object to > > > read in XML from an XML file and it's not working. I'm sure there's > > > something really simple I'm just overlooking. I've been comparing it > to > > > code I found on the web that definitely works and can't figure out > what > > > the difference is aside from try catch statements (maybe that's it?). > > > Anyway, this is the code. Basically, I'm just trying to get an > > > acknowledgment that it actually read in XML from the file but Firefox > > > says the xmlDoc object is null... and while IE recognizes the object, > > > any processing I do on it fails. > > > Thanks for any help! > > > function addMovies() { > > > var req = null; > > > if (window.XMLHttpRequest) { > > > req = new XMLHttpRequest(); > > > } else { > > > if (window.ActiveXObject) { > > > req = new ActiveXObject(" > > > Microsoft.XMLHTTP"); > > > } > > > } > > > req.onreadystatechange = function() { > > > if (req.readyState == 4) { > > > if (req.status == 200) { > > > var xmlDoc = > > > req.responseXML; > > > window.alert(xmlDoc); > > > document.getElementById > ("theClicker").disabled > > > = true; > > > } else if (req.status == 404) { > > > window.alert("The > requested > > > URL does not exist!"); > > > } else { > > > window.alert("Error: > status > > > code = " + req.status); > > > } > > > } > > > }; > > > req.open("GET", "ajaxtest.xml", true); > > > req.setRequestHeader("Content-Type", > "text/xml"); > > > req.send(null); > > > } > > ------=_Part_91268_366310.1163801434935 > > Content-Type: text/html; charset=ISO-8859-1 > > Content-Transfer-Encoding: quoted-printable > > X-Google-AttachSize: 6859 > > <div>Read this:</div> > > <div></div> > > <div><a href=3D" > http://radio.javaranch.com/pascarello/2006/09/12/1158096122600.html"> > http://radio.javaranch.com/pascarello/2006/09/12/1158096122600.html > </a></div> > > <div></div> > > <div>Eric<br><br></div> > > <div><span class=3D"gmail_quote">On 11/17/06, <b > class=3D"gmail_sendername">The alMIGHTY N</b> <<a href=3D"mailto: > natle@yahoo.com">natle@yahoo.com</a>> wrote:</span> > > <blockquote class=3D"gmail_quote" style=3D"PADDING-LEFT: 1ex; MARGIN: > 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"><br>Hi there -- I've been > trying to get a basic XMLHttpRequest object to<br>read in XML from an XML > file and it's not working. I'm sure there's > > <br>something really simple I'm just overlooking. I've been comparing it > to<br>code I found on the web that definitely works and can't figure out > what<br>the difference is aside from try catch statements (maybe that's > it?). > > <br><br>Anyway, this is the code. Basically, I'm just trying to get > an<br>acknowledgment that it actually read in XML from the file but > Firefox<br>says the xmlDoc object is null... and while IE recognizes the > object,<br>any processing I do on it fails. > > <br><br>Thanks for any help!<br><br> function addMovies() {<br> var req > =3D null;<br> if (window.XMLHttpRequest) {<br> req =3D new > XMLHttpRequest(); > > <br> } else {<br> if (window.ActiveXObject) {<br> req =3D new > ActiveXObject("Microsoft.XMLHTTP");<br> } > > <br> }<br> req.onreadystatechange =3D function() {<br> if ( > req.readyState =3D=3D 4) {<br> if (req.status =3D=3D 200) {<br> > > var xmlDoc =3D req.responseXML;<br> window.alert(xmlDoc);<br> > document.getElementById > > ("theClicker").disabled =3D true;<br> } else if (req.status =3D=3D 404) > {<br> window.alert("The requested URL does not exist!"); > > <br> } else {<br> window.alert("Error: status code =3D " + req.status);<br> > }<br> } > > <br> };<br> req.open("GET", "ajaxtest.xml", true);<br> > req.setRequestHeader("Content-Type", "text/xml");<br>=20 > > req.send(null);<br> }<br><br><br></div><br>=0A > > ------=_Part_91268_366310.1163801434935--