Hi Naved,
In your case, simply remove the height attribute from that table tag. You
will find it does not change the display.
Occasionally one needs to actually achieve a particular height for the table
in order for things to fit properly on the page. In those cases instead of
using height="113" in the table tag use style="height: 113px;" and it will
have the same effect but be valid. Or use height attributes on individual
td elements inside the table, the td with the largest height value will give
the overall table height.
These type of validation errors don't affect anything as far as SEO is
concerned. Occasionally they may affect rendering in some browsers.
Other kinds of much more serious errors may affect robots' ability to
properly read the content. Like javascript code that may be getting mixed up
with html because it is not encoded properly, or improperly nested or closed
tags, especially in the head section. I cannot give a percentage, it really
depends on what the errors may be.
And more than validation errors, using the wrong markup may also affect
optimization. For instance it's known that using proper header tags (h1, h2,
etc) adds semantics to the markup. Keywords and keyphrases found within
header tags have a little more weight than when they are found in regular
text. If you were to have something like this:
<div class="h1">Services offered by company ABC"</div>
it would be much better to use:
<h1>Services offered by company ABC</h1>
even though they may be displayed exactly the same way in the browser
(according to how you styled the class h1 or the header tag h1).
You can use css to style both the class h1 and the header tag h1
identically. But while the h1 tag adds importance to the text, the class h1
only styles the content and adds no special meaning or importance to the
text.
You can say then that proper use of header tags (h1, h2, ...) improves the
optimization of the page. Of course they must be used properly, not for
styling and not for tricking the robot into believing that everything is
important. Too much of that ends up being ignored altogether, you cannot
just wrap all your text in header tags. The importance is always relative to
the rest of the text, that's what a header is supposed to achieve in any
well written text document, whether we are talking about a web page or an
article in a newspaper or in a magazine.
Christina
www.webado.net