How to create a tree structure in Javascript DOM?

StackOverflow https://stackoverflow.com/questions/1417940

  •  07-07-2019
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Question

This is going to sound too silly / too basic - sorry about that, but I experimented a lot and couldn't come to the right solution!

I'm using this following piece of code - which makes a row of text fields go up and down. Unfortunately, the up and down movement doesnt stop and carries on throughout the page! :)

function up(row) {
    // need to stop somewhere
    var prevRow = row.previousSibling;
    if(prevRow != null) {
        row.parentNode.insertBefore(row, prevRow);
    }
};

function down(row) {
    // need to stop somewhere as well
    var nextRow = row.nextSibling;
    row.parentNode.insertBefore(row, nextRow.nextSibling);
};

My generated html is a combination of xml and xsl. The XSL looks like this:

<xsl:for-each select=".../...">
<p>
<button type="button" onclick="up(this.parentNode)">Up</button>
<button type="button" onclick="down(this.parentNode)">Down</button>
<input>
...
...
...
</p>
</xsl:for-each>

As described above, this works, but the up and down movements dont stop. I tried enclosing the xsl:for-each in another p tag, and a div tag, but neither worked. I was trying to have the parent of these p tags as something other than the body tag.

Did I make myself clear?

Generated HTML added below:

<html>
<head>
<script>
function up(row) {
...
};
function down(row) {
...
};
</script>
</head>
<body>
<form name="edit_form" action="edit.php" method="POST">
...
<?xml version="1.0"?>
...
<p>
<button type="button" onclick="up(this.parentNode)">Up</button>
<button type="button" onclick="down(this.parentNode)">Down</button>
<input name="CRorder[record10354881]" type="text" value="0" disabled="" size="4"/>
<input name="CRpreference[record10354881]" type="text" value="10" disabled="" size="4"/>
<input name="CRlabel[record10354881]" type="text" value="label1"/><input name="CRvalue[record10354881]" type="text" value="22222222222"/></p>
<p><button type="button" onclick="up(this.parentNode)">Up</button>
<button type="button" onclick="down(this.parentNode)">Down</button>
<input name="CRorder[record10354882]" type="text" value="1" disabled="" size="4"/>
...
...
</form></body>
</html>
Was it helpful?

Solution

Based on your HTML, and assuming the ...s do not contain matched pairs of tags that will make the P a child, the P containing the Up/Down buttons (and other paraphinalea) will move up the list of Ps until it is the first child of the FORM tag. As this is directly adjacent to the BODY tag, this is, in effect, moving it all the way up the page.

Edit: OK, from your comment, if you have other siblings to the P tags that you don't to move them past, you'll need to mark them somehow and change your up/down functions to obey those limits. Something like...

...<tag id="upperLimit">...

function up(row) {
  // need to stop somewhere
   var prevRow = row.previousSibling;

   if(prevRow != null && prevRow != document.getElementById("upperLimit")) {
     row.parentNode.insertBefore(row, prevRow);
  }
};

with a similar restriction on the lower limit.

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