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Book review: JQuery Mobile – a first look |
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I was recently sent a copy of JQuery Mobile by Packt publishing for review. I've dabbled in the JQuery Mobile development language a fair amount, so I was interested to see what this book could teach me that may be different from the information out there in the community.
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Handling JavaScript event model differences in Internet Explorer and Firefox |
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A few weeks ago I created an inline editing system for a Content Management System. It allowed a user to click on a page element and edit it inline. The updated data was then submitted through an AJAX request.
I have recently discovered an issue with some of the JavaScript code that I wrote in the event handling routine.
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Creating a CSS only cross browser drop down menu |
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I'll say this up front, I'm not a CSS guru. I like CSS, but it can be incredibly frustrating. One of the clients I am currently producing work for requires a high level of Accessibility. High enough that we need to avoid using JavaScript unless any script has a "Non" JavaScript equivalent.
The site navigation is through a top level horizontal menu, but what if we also want a drop down menu? Can we do it in CSS only, and it still be Firefox, Internet Explorer 6,7 and 8 compatible?
Yes, we can, but it's a lot of code, and it's not pretty. The basic concept behind most CSS menus is to use a list, and transform each list item to suit your styling. So we will create a div, with a class of menu. Then create a list inside it.
2 <ul>
3 <li><a href="">Top menu option
4 <!--[if IE 7]><!--></a><!--<![endif]-->
5 <!--[if lte IE 6]><table><tr><td><![endif]-->
6
7 <ul>
8 <li><a href="">Link 1</a></li>
9 <li><a href="">Link 2</a></li>
10 <li><a href="">Link 3</a></li>
11 <li><a href="">Link 4</a></li>
12 <li><a href="">Link 5</a></li>
13 <li><a href="">Link 6</a></li>
14 </ul>
15
16 <!--[if lte IE 6]></td></tr></table></a><![endif]-->
17 </li>
18
19 </ul>
20
21 </div>
Notice that there are some specific if statements relating to different versions of Internet Explorer. these basically make the functionality the same for each version, they are compensating for the differences in code handling between IE versions.
Next create a set of CSS styles to alter the appearance of the list. I am not going to go into the CSS line by line, as it is commented, but I'll explain the methodology behind it.
The top level menu item is always displayed, but the list is hidden using "visibility:hidden". When the user mouse's over the menu div the CSS applies a:hover ul{visibility:visible;. This makes the list visible.
2
3.menu {width:149px; height:32px; position:relative; z-index:100;border-right:1px solid #000; font-family:arial, sans-serif;}
4
5/* hack to correct IE5.5 faulty box model */
6* html .menu {width:149px; w\idth:149px;}
7
8/* remove all the bullets, borders and padding from the default list styling */
9.menu ul {padding:0;margin:0;list-style-type:none;}
10.menu ul ul {width:149px;}
11
12/* float the list to make it horizontal and a relative position so that you can control the dropdown menu positon */
13.menu li {float:left;width:149px;position:relative;}
14
15/* style the links for the top level */
16.menu a, .menu a:visited {display:block;font-size:12px;text-decoration:none; color:#fff; width:138px; height:30px; border:1px solid #000; border-width:1px 0 1px 1px; background:#c0c0c0; padding-left:10px; line-height:29px; font-weight:bold;}
17
18/* a hack so that IE5.5 faulty box model is corrected */
19* html .menu a, * html .menu a:visited {width:149px; w\idth:138px;}
20
21/* style the second level background */
22.menu ul ul a.drop, .menu ul ul a.drop:visited {background:#c0c0cc url(arrow.gif) no-repeat 130px center;}
23
24/* style the second level hover */
25.menu ul ul a.drop:hover{background:#c0c0cc url(arrow.gif) no-repeat 130px center;}
26.menu ul ul :hover > a.drop {background:#c0c0cc url(arrow.gif) no-repeat 130px center;}
27
28/* hide the sub levels and give them a positon absolute so that they take up no room */
29.menu ul ul {visibility:hidden;position:absolute;height:0;top:31px;left:0; width:149px;border-top:1px solid #000;}
30
31/* another hack for IE5.5 */
32* html .menu ul ul {top:30px;t\op:31px;}
33
34/* style the table so that it takes no part in the layout - required for IE to work */
35.menu table {position:absolute; top:0; left:0; border-collapse:collapse;}
36
37/* style the second level links */
38.menu ul ul a, .menu ul ul a:visited {background: ghostwhite; color:#000; height:auto; line-height:1em; padding:5px 10px; width:128px;border-width:0 1px 1px 1px;}
39
40/* yet another hack for IE5.5 */
41* html .menu ul ul a, * html .menu ul ul a:visited {width:150px;w\idth:128px;}
42
43/* style the top level hover */
44.menu a:hover, .menu ul ul a:hover{color:#000; background:#c0c0cc;}
45.menu :hover > a, .menu ul ul :hover > a {color:#000; background:#c0c0cc;}
46
47/* make the second level visible when hover on first level list OR link */
48.menu ul li:hover ul,
49.menu ul a:hover ul{visibility:visible;}
There are also a lot of other browser specific hacks present, as the aim was to get the menu working in every Internet Explorer version, and be Accessible.
There is a demo of this here: CSS menu demo
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My handy IE CSS tweaks list |
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I'm not really a design kind of person, I like designing things, and I'm learning more and more CSS all the time, but it's the server side coding that I love like Apple Pie and custard.
Recently I've had to do a bit more design work, so I've been tripping all over myself to get CSS working in IE6,IE7,IE8 and firefox. I've learnt a few interesting things in the last few days, and I know I'm going to need to use them again. Some are considered 'hacks', some are just clever CSS techniques. They all feel a bit like secret rules of a club I'm not really a member of yet though.
So I'm making a handy list, so I don't loose them. I hope to refine and add to this on an ongoing basis, so if you know a better / easier way please let me know. After all coding standards are for life, not just Christmas, and I don't like the idea of anything being a hack, even if it is CSS.
Adding a 1px high line to IE
I am trying to add a 1px line, like a HR line to the page, it displays fat in IE?It seems that some versions of IE will display a div without content as the same height as your font size. Add html comments to it to drop it down to the right height:
2.yellow-ruler {color: #ffd520; background-color:#ffd520; width: 100%; height:2px; margin: 3px 0px 0px 0px;}
3</style>
4<div class="yellow-ruler"><!-- --></div>
IE is adding padding and margins to everything by default
I think there is a lot more information about this out there, but for now I've found that adding the code below will kill most of IE's random padding/margin issues.
I've built a JQuery accordion and the content doesn't move correctly
When expanding a JQuery accordion element the content underneath it is not moving down, and the accordion is expanding over it. This was a simple fix, but a bit of a pain to find. Just do not specify a height attribute on the div that hold the accordion, IE will stick to the height, but firefox will let it grow to be longer.
Styling form element borders
If you have a CSS rule like the one above that removes all the margins, padding and borders then all your form elements will have no border. IE your text fields and textareas etc will not have a clearly defined edge to them. By adding the line of CSS under this (select,input, etc) you can set the style width and colour of your form elements so that you control them, rather than the browser defaults. In Internet explorer this will also add borders to the checkbox and radio form elements. There does not seem to be any way of writing a CSS style to remove this inherently, so create a style of borderless and set all your radio and checkbox fields to "class=borderless".
2
3select,input,textarea{border-width: 1px; border-style: solid; border-color: grey;}
4
5/* IE stops the radio borders */
6.borderless{border: 0px;}
Strange IE positioning fix
Sometimes in IE (mainly 6) using position: absolute just does not render the div on screen. I am not sure why. Adding a "clear: both;" or a "clear: left;" or a "clear: right;" appears to fix this.
Easy centering of elements
I used to struggle with centering elements on a page all the time, but now you can do something like this:
2 margin-left: auto;
3 margin-right: auto;
4 width: 6em
5}
6
7<p class="blocktext">Text</p>
This will center a block of text and give it a width of 6.
For images you can do this:
2 display: block;
3 margin-left: auto;
4 margin-right: auto }
5
6<img class="displayed" src="..." alt="...">
That will auto center the image inside its containing div.
