CSS2's advice as early as 1998, the table will gradually fade out the stage, slowly go down in history. And that is why CSS layout became synonymous with elegant coding.
in the concept of all CSS designers used in negative margin should be positioning method of the least, it's like a taboo, everyone use it, but nobody to talk about it.
1, negative margin“ Rehabilitate &throughout;

code is as follows:

# content {margin - left: - 100 px; }

normally people seldom use negative margin but then you will know that actually have a lot you can do it. Here are A few relevant negative margin where need to pay attention to:
A and negative margin is absolute standard CSS
this is not A joke. W3C note: even for margin properties, a negative value is allowed, it is
B, Nuff said negative maring is not a way to hack
true, can't because of a lack of understanding of the negative marign or because it looks like a hack, as it is a way to hack. Unless you are used to repair their errors in other place.
C, not from the document flow
do not use the float, is negative margin elements won't destroy the document flow of the page. Negative margin up so if you use an element, all elements will be follow up.
D, fully compatible with all modern browsers,
fully supports the negative margin (also support IE6 in most cases).
E, float will affect the use of negative margin
negative margin is not every day you use CSS properties, the application should be cautious.
F, Dreamweaver is not analytic negative margin
DW design view will not be parsed by a negative margin. But the question is why do you want to check your website in design view?
2, using the negative margin

code is as follows:

/* element moving upward 10 px # */
mydiv1 {margin - top: - 10 px; }

but if you set the margin - bottom/right is negative, the elements are not moving down/right as much as you think, but the subsequent element drag to come in, cover elements.

  code is as follows:  

*/* # mydiv1 subsequent element moving upward 10 px, # mydiv1 itself does not move/

* # mydiv1 {margin - bottom: - 10 px; }

if you don't have to set the width attribute, set the negative margin - left/right will put off towards the direction of the corresponding element, and increase the width of the margin of the role as padding.
3, negative margin on the floating element
code is as follows:

<Div id="mydiv1 >" First