GrandFather thanks for your assistance. Here the section closings are correctly nested.

<sec id="00005"><no>1.1</no>
sfasfasdfadsfsdaf
    <sec id="00010"><no>1.1.1</no>
    sahfjsahdfasddfj
    </sec
    <sec id="00015"><no>1.1.2</no>
    sahfjsahdfasddfj
        <sec id="00020"><no>1.1.2.1</no>
        sahfjsahdfasddfj
        </sec>
        <sec id="00025"><no>1.1.2.2</no>
        safksajdklfasd
        </sec>
    </sec>
    <sec id="00015"><no>1.1.3</no>
    sahfjsahdfasddfj
    </sec>
</sec>
<sec id="00005"><no>1.2</no>....
[download]

This is bad example

<sec id="00005"><no>1.1</no>
sfasfasdfadsfsdaf
    <sec id="00010"><no>1.1.1</no>
    sahfjsahdfasddfj
    </sec
    <sec id="00015"><no>1.1.2</no>
    sahfjsahdfasddfj
        </sec>                     #it should not be closed here (beca
+use next sublevel is opening here)
        <sec id="00020"><no>1.1.2.1</no>
        sahfjsahdfasddfj
        </sec>
        <sec id="00025"><no>1.1.2.2</no>
       safksajdklfasd
    </sec>                     #that should be closed here
    <sec id="00015"><no>1.1.3</no>
    sahfjsahdfasddfj
    </sec>
</sec>
<sec id="00005"><no>1.2</no>....
[download]

Whereas here the second level section should close after third level is closed. This is wrong nesting. Actually the levels are identified by number with dots.

1.1 - first level
1.1.1 - second level (first section's sub level)
1.1.1.1 - third level (second section's sub level)
1.1.1.1.(i) - fourth level (third section's sub level)
1.1.1.1.(i).(a) - fifth level (fourth section's sub level)
[download]

Here the elements are same for all levels <sec, so parser not showing errors. If the elements are different for subsections like <sec, <sec1 , <sec2, the parser would have showed error. so here the nesting we are finding with the help of numbers 1.1, 1.1.1,...

updated

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.