Problem with looping over attributes in XML->DOM

[louissan]

Hi all,


I'm coming across a problem, and really do not get where it comes
from.

The goal: to loop over attributes read from "object" nodes in an
imported XML file/flow (via XMLHTTP) and transform them into HTML/DOM
attributes.


The function ObjectList reads from the imported XML and calls the
needed functions to 'render' DOM nodes.

function objectList(obje ct,usersrc) {
var attlist=new Array();
var objs = usersrc.getElem entsByTagName(o bject);
for (i=0;i<objs.len gth;i++) {
alert(objs.leng th); // reads 5, but the loop stops at 0 :(
var obj;
for (j=0;j<objs[i].attributes.len gth;j++) {
attlist[j]='"'+objs[i].attributes[j].nodeName+'|'+o bjs[i].attributes[j].nodeValue+'"';
}
var objType = objs[i].getAttribute(' type');
if (objType=='anch or') obj = new anchor(attlist) ;
else {obj=null,alert ('no type specified');}
// append child nodes
document.getEle mentById(object ListId).appendC hild(obj);
}
}

The anchor function creates the node in the DOM

var a_att="..."; // list of valid W3C anchor attributes

function anchor(attlist) {
var att,attval;
newanchor = document.create Element('a');
for (i=0;i<attlist. length;i++) {
att = attlist[i].substring(1,(a ttlist[i].indexOf(sep))) ;
attval = attlist[i].substring(attl ist[i].indexOf(sep)+1 ,attlist[i].length-1);
new Function ( 'if (a_att.indexOf( att)!=-1) {newanchor.' + att +
'="' + attval + '";}' );
}
var anchortext = new textNode('test' );
newanchor.appen dChild(anchorte xt);
return newanchor;
}

If my imported XML file looks like this:

<root>
<menu type="anchor" href="test.jsp" cssClass="top"
icon="test.gif" >overview</menu>
<menu type="anchor" href="test.jsp" cssClass="top"
icon="test.gif" >overview</menu>
<menu type="anchor" href="test.jsp" cssClass="top"
icon="test.gif" >overview</menu>
<menu type="anchor" href="test.jsp" cssClass="top"
icon="test.gif" >overview</menu>
<menu type="anchor" href="test.jsp" cssClass="top"
icon="test.gif" >overview</menu>
</root>

The ObjetList loop stops at i=0. Why? Any clue?

Thanks :)

[Dietmar Meier]

Re: Problem with looping over attributes in XML-&gt;DOM

louissan wrote:
[color=blue]
> function objectList(obje ct,usersrc) {
> [...]
> for (i=0;i<objs.len gth;i++) {
> [...]
> if (objType=='anch or') obj = new anchor(attlist) ;
> [...]
> function anchor(attlist) {
> [...]
> for (i=0;i<attlist. length;i++) {
> [...][/color]

You use the same _global_ variable i in both functions.
See ECMA-262 section 12.2 for details.

ciao, dhgm

[Martin Honnen]

Re: Problem with looping over attributes in XML-&gt;DOM



louissan wrote:

[color=blue]
> function objectList(obje ct,usersrc) {
> var attlist=new Array();
> var objs = usersrc.getElem entsByTagName(o bject);
> for (i=0;i<objs.len gth;i++) {
> alert(objs.leng th); // reads 5, but the loop stops at 0 :([/color]

You need to learn to use local variables as much as possible, in
particular loop variables should always be local to a function otherwise
if you call into another function that use the same variable you get all
sort of unwanted side effects.
Thus use
for (var i = 0; ...)[color=blue]
> var obj;
> for (j=0;j<objs[i].attributes.len gth;j++) {[/color]

and
for (var j = 0; ...)
[color=blue]
> function anchor(attlist) {
> var att,attval;
> newanchor = document.create Element('a');
> for (i=0;i<attlist. length;i++) {[/color]

and
for (var i = 0;
and then start again, your code is more likely to do what you want now.

Note that I haven't checked all your code carefully, there might be
other problems, but once you fix the variables to be local to the
functions you can post back if there are still problems.


--

Martin Honnen

http://JavaScript.FAQTs.com/

[louissan]

Re: Problem with looping over attributes in XML-&gt;DOM

The local variables were indeed the problem :)

[Martin Honnen]

Re: Problem with looping over attributes in XML-&gt;DOM



louissan wrote:
[color=blue]
> The local variables were indeed the problem :)[/color]

No, the lack of local variables were the problem.


--

Martin Honnen

http://JavaScript.FAQTs.com/