things NN won't do

when NN fails to respond intuitively

page 5 of 8

page 1
• margins and headers
• margins and headers with width
page 2
• setting div margins in a table cell
• setting div width in a table cell
• adding a border
page 3
• setting color of text in tables
• name anchor references
page 4
• closing table tag
• span tag
• negative margins
page 5
• broken images and alt text
• the title attribute
page 6
• the height attribute
page 7
• the pseudo classes
page 8
• iframes

broken images and alt text

The ALT attribute of the IMG tag is an increasing important element of a webpage. Let's look at how IE5.0 and NN4.7 deal with the ALT attribute for broken images. Broken images are images that do not load for one reason or another, usually because the graphic file is not where the IMG tag is pointing.

The code below calls for two images, neither of which exists. One has its HEIGHT and WIDTH attributes set, one does not.

<hr>
<img src="nowhere.gif" alt="a broken image">
<hr>
<img src="nowhere.gif" alt="a broken image" height=100 width=200>
<hr>

we see in NN4.7:	we see in IE5.0:
we see in NN6.0:	.

The first image has no dimensions set. NN4.7 and IE5.0 simply extend the area of the broken image placeholder out to display the ALT text. In the second broken image, there is ample room to display the ALT text straight across the placeholder area

For both situations, NN6.0 simply displays the ALT text. There seems to be no dimensions laid out for the missing picture. This is a little disturbing.

In the next example, let's make the ALT text verbose and see what happens.

<img src="nowhere.gif" 
alt="a broken image and this description is big"
   height=100 width=200>
<hr>

we see in NN4.7:	we see in IE5.0:

What has happened is the ALT text is too big for NN4.7 to display in the placeholder area without breaking, so it doesn't display it at all. IE5.0 simply breaks the ALT text in the placeholder area. NN6.0, since it doesn't draw a box the size of the graphic, just displays the ALT text in one line.

the title attribute

IE5.0 and NN6.0 support an additional attribute in the IMG tag, the TITLE attribute. The TITLE attribute is similar to the ALT attribute. If the TITLE attribute is present, mousing over an image will give the TITLE and not the ALT. Broken images display the ALT, with the TITLE mouseover. This gives flexibility as to what information the user gets in a mouseover. NN4.7 doesn't support this at all.