CODEWITHSUNDEEP
javascriptxmlgetelementsbytagname
Saturnix
Saturnix

Reputation: 10564

XML file in Javascript, getElementByAttribute

Let's suppose I have an XML file like this:

<?xml version="1.0" encoding="ISO-8859-1"?>
<MIDIFile>

  <Event>
    <Absolute>0</Absolute>
    <NoteOn Channel="1" Note="40" Velocity="64"/>
  </Event>
  <Event>
    <Absolute>236</Absolute>
    <NoteOff Channel="1" Note="40" Velocity="0"/>
  </Event>

</MIDIFile>

Thanks to some great tutorial I now know how to get these values in my javascript.

For example, I can iterate thru all the "Events" tag and get the "Absolute" value like this:

xmlhttp=new XMLHttpRequest();

xmlhttp.open("GET","test.xml",false);
xmlhttp.send();
xmlDoc=xmlhttp.responseXML;

// make an array with all the events from the xml file
var events = xmlDoc.getElementsByTagName("Event")


for (var i = 0; i<events.length; i++)
console.log(events[i].getElementsByTagName("Absolute")[0].childNodes[0].nodeValue)

this will return

0
236

Now, how the hell can I access the "NoteOn" attribute and get its values? I want to iterate thru all the Events in the XML, see if they contains NoteOn or NoteOff and load an array with all the notes, their duration, velocity and channels.

Please help me! getElementsByTagName("NoteOn") just doesn't work... If it might help, here are some screenshot of what happens if I console.log(xmlDoc)

Thanks a lot in advance!

screen

edit in response to an answer. As I try to do this:

var noteon = xmlDoc.getElementsByTagName('noteon');
console.log(noteon)

the result is just this one

[]

re-edit: If I write "NoteOn" instead of "noteon" it works!

Upvotes: 1

Views: 1335

Answers (1)

Ryan
Ryan

Reputation: 5682

var noteon = xmlDoc.getElementsByTagName('noteon');
var note = new Array;
for(var i = 0; i < noteon.length; i++){
    note[i] = noteon[i].getAttribute('Note'); // or any of the attributes you want to get
}

Edit:

If noteon = [] then you have 2 options you can put the whole thing in a try catch, not the best thing to do in javascript, or you can put it in an if statement. Something like this should work:

var noteon = xmlDoc.getElementsByTagName('noteon');
var noteoff = xmlDoc.getElementsByTagName('noteoff');
var note = new Array;

if(noteon != []){
    for(var i = 0; i < noteon.length; i++){
        note[i] = noteon[i].getAttribute('Note'); // or any of the attributes you want to get
} else if(noteoff != []){
    for(var i = 0; i < noteoff.length; i++){
        note[i] = noteoff[i].getAttribute('Note'); // or any of the attributes you want to get
} else{
    return;  //makes sure the function returns to the call even if nothing was found
}
}

Upvotes: 4

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