Question 50 for the application of div css layouts

Defines the top, bottom, left, and right margins for blue. The width is 100%.

Since the left and right are both in main, the red and blue margins relative to the main are customized.

Helped you optimize the structure or something, I feel that your writing is too messy, can you see if it is the effect you want?

The full ** is as follows:

When I put it on the side, the outside is there. left external plus a width: 100% to welcome me to my group 21194723 if you have any questions

The changes are as follows, if it is not correct, it may be because you did not ask clearly enough.

right and. left, add below**.

position:absolute; left:0px; top:50px;

1. The layout follows the principle of from the whole to the part. You can try to design the relationship between the div blocks, including or juxtaposing.

2. When juxtaposing blocks, you can use the float attribute, and ensure that the sum of the widths of these two blocks is less than its parent block when using float, otherwise there will be a broken line.

3. When the block with the float attribute applied, the block has been out of the normal document flow, so the block under it will be as if it does not exist, and it needs to be cleared at this time

1. Be sure to float after floating, try to use floating as little as possible to layout, and keep even columns more stable if you have to use them.

2. Do not use a single paragraph tag under h3.

3. Reduce nesting to avoid errors caused by duplicate IDs in functional programs.

4. Try not to use borders, because different browsers interpret borders differently, which can easily lead to width errors.

5. Try not to use absolute height to limit the float project, that is just a waste of effort, hurry up and enrich the core content of **.

Skill. As long as you are familiar with the various properties of CSS, it is fine. Pay attention to the compatibility of various browsers.

My train of thought is as follows:

1. Set the outermost layer (div 1) to width: 100%.

2. There are two small layers in div 1 1 and div 1 2, the width is 49% and 50% respectively, and the float is left

3. Put a small layer of div 1 1 1 in div 1 1, fix the width, and float is left

4. Put a small layer of div 1 2 1 in div 1 2, fix the width, and float to right

Principle] Because the innermost two fixed-width layers are two different layers, they do not change as the width of the browser changes.

The two large layers each account for 50%, so no matter how small the browser width is, they will not fluctuate up or down.

Unless the width of the browser is less than the sum of the widths of the two fixed layers.

Just think about it from another angle.

The two divs in the container, the one on the left floats to the left, and the margin-left one sets a value for him, and the one on the right floats, and the margin-right sets a value for him.

Isn't that just ...

You can set min-height or min-width, which means the minimum value of your height and width.

There are more methods, and there are roughly two kinds of methods used at present, although CSS3 directly provides relevant properties, but it is not necessary to wait for it to become popular.

1 is pure CSS, build a lot of grid bars, the lower layer is more or less than the upper layer by one pixel, fill in the solid color, about 6 to 8 layers can make a small arc. This master may have used it, but now many people don't use it, because this one is not only a bit troublesome, but also only makes a solid color frame. Besides, now that the network speed is fast, the background is only a few k, and it is easy to load, so the following method is more mainstream.

2 is a combination of CSS and diagramming, and draw a border with an arc with ps or something.

You can just draw a complete rounded rectangle and lay it on the div with a background:url (**address), which is fixed in length and width.

To make the box wider and longer, you need to divide the rounded rectangle and combine it with properties such as overflow:hidden or repeat:y. It is divided into several pieces depending on personal habits or specific requirements.

Paste a related picture that I did before.,If you don't understand, let's talk about it.。

CSS3 is fine, but now only the latest versions of browsers, such as Google Chrome, support CSS3.

First, the first streamlined.

Using div+css layout, the page is streamlined, which I believe anyone who knows XHTML knows. **There are two direct benefits of streamlining: one is to improve the efficiency of spider crawling, which can crawl the whole page in the shortest time, which has certain benefits to the quality of the collection; The second is that because it can crawl efficiently, it will be liked by spiders, which will have a definite benefit to the number of people included.

Second, the nesting problem of **.

With the table layout, in order to achieve a certain visual effect, you have to apply multiple **. If the core content is in the nested **, and the spider skips this paragraph when crawling and does not crawl to the core of the page, the page becomes a similar page. Too many similar pages can affect rankings and domain trust.

The div+css layout basically doesn't have this problem, and from a technical point of view, xhtml doesn't need to be too nested when controlling styles.

Although this has not been confirmed, it is still recommended that friends who use the table layout should not use multi-layer ** nesting as much as possible in the design, and the seoers explained this in the article, and I believe they are not without basis.

Third, the issue of speed.

The div+css layout has fewer pages** than the table layout, and the loading speed is greatly improved, which is very advantageous when spiders are crawling. Too many page code codes may cause crawling timeouts, and the spider will think that the page is inaccessible, affecting the inclusion and authority.

On the other hand, a real SEO is not only for the pursuit of inclusion and ranking, but also for fast response speed is the basis for improving user experience, which is very beneficial to the entire search engine optimization and marketing.

Fourth, the impact on the ranking.

The DIV+CSS layout based on the XTHML standard is generally as complete as possible after the design is completed to pass W3C verification. So far, no search engine has indicated that the ranking rules will favor W3C-compliant ** or pages, but it turns out that ** using the XTHML schema generally ranks well. This point may be controversial, but Le Sishu himself maintains such a view, and those who disagree can compare and observe more than three groups of ** of basically the same quality.

Less layout than Table, div only needs content and table wants content.

It is loaded in blocks, as long as the content of a div is transmitted to the local distribution of the web page, it can be displayed, and the table needs to wait until the content of the table is all transmitted and displayed together, so that the user feels less waiting time.

2: The resolution problem is also a CSS problem, for example, the total width of your div layout is 1000pxThen the display with a resolution of 1024*768 or more will not be a big problem, but 800*600 will be misaligned. For this.

A few points to note, here for the sake of convenience and clarity, I added border, border will be added to the width, and the accumulation of each border needs to be calculated by yourself;

2. There are some positions: relative positioning, which can be effectively compatible with various browsers, used for position and float, basically do not need to write browser compatible styles, in addition, for IE6, the margin is less padded, because his calculation method is different from other browsers.

3. Here is written the property of the border, in the IE table other browsing, the parsing algorithm of IE is different, so the browser of the IE kernel will be a little biased, if you want to do not deviate, you can write a style in IE, or the style is compatible, or add a processing at the outermost edge of each layer.

1. Set the height.

2. Width plus height plus left floating.

3, 4, 5, 6 and 2 all float on the left and have width and height.

It's best not to add up the width = 700 to include the px width of the border, otherwise the width won't be accommodated

There you go, go give it a try.

<>I've got you this total width of 508 pixels, closed.

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