Recently I coded an interesting photo gallery using jQuery. I’ve named it “jQuery Mix Photo Gallery”. I’ve included the screen-shots here.
You may have a look at the live demo here. The photo gallery is free to download. Here is the download link. You may modify it according to your need and use it in your commercial projects. Please drop a comment if you like it and suggest me how can I make it much better.
You already know ajax is one-man’s-girl, no way to make it work cross-domain(not even subdomain) due to browsers’ same origin policy security restriction. But using ajax is so sleek, you can’t even resist yourself using it under different domains. There is always a way around for everything. Do I sound contradictory? Ajax is based on the XMLHttpRequest and as long as we use it we can’t do cross-domain data transfer. Let’s think something else other than ajax.
We are used to loading images, css, javascript files from other domains and it’s okay if we use any server-side dynamic link as the src, this is a common phenomena on web. For example:
<script type="text/javascript" src="http://www.other-domain.com/dynamic-js.php?id=5&name=Matt"></script>
There is no security restriction including javascript source from different domains, and fortunately enough you can pass GET variables (don’t over-expect for POST) with the url. This is how JSONP (JSON with padding) works, thanks to the open policy for <script> tag. May be you’r already thinking how to implement this idea, hold on! you don’t need to reinvent the wheel.
Here comes jQuery’s $.getJSON(), with this function you can pass url of another domain and get JSON data. Lemme warn you, for the very first time most of you won’t be able to make it work. Here is an example:
$.getJSON("http://www.other-domain.com/dynamic-js.php?id=5&name=Matt&jsoncallback=?",
function(data){
// your code goes here
});
You need to understand this “jsoncallback=?” bit clearly. From your firebug Net panel you can see the “?” is replaced with “jsonp1277557614558″ (random value on each request).
The common mistake you’re gonna do is you expect to see something on firebug’s Console tab, but nothing there, once again JSONP is NOT Ajax request. This is merely an external javascript file being added to your document dynamically, if you don’t believe me on your firebug panel click the JS from Net tab to filter out the JS only(marked in the screen-shot above). You’ll definitely see the JSONP url there. This is the client-side part of $.getJSON(). The confusion still remains with the server-side code.
Back to “http://www.other-domain.com/dynamic-js.php?id=5&name=Matt&jsoncallback=?”, the file being called is dynamic-js.php. Put this one line of code in that file:
<?php print_r($_GET); ?>
And check the Response output from firebug’s Net tab. It’ll be something like:
Array
(
[id] => 5
[name] => Matt
[jsoncallback] => jsonp1277557614558
)
In Ajax when the dataType is json the response from server-side script is just the json string:
{
// your json data
}
Here is the most important part, unlike ajax for JSONP the $.getJSON() expects the response like:
jsonp1277557614558({
// your json data here
})
So you must wrap the json output with jsonp1277557614558( ). If you don’t do it the callback will fail silently without any error, which makes it tough to detect the exact problem. Remember the jsonp1277557614558 is a random string. For php the code will be something like this:
<?php
// your code here
// get the output in an array say $output_array
$jc = $_GET['jsoncallback'];
echo $jc . '(' . json_encode($output_array) . ')';
/*
// For ajax response, simply
echo json_encode($output_array);
// is enough
*/
?>
This is the most crucial thing, most programmers do the mistake for their very first time as there is no clear elaboration on $.getJSON documentation page. FYI, json_encode() function is not available on older version of php. You can get the php class from json.org.
Hope your $.getJSON() is now working! :)
Comments, criticism are most welcome.
Once upon a time people used tables for designing website layout. Definitely table tag has many advantages but it’s not that flexible & extensile. You can not use proper positioning or floating attributes css style for table based layout. It’s not that commodious to handle table width/height from Dreamweaver, the layout gets messy when you drag any border of table, td or tr as the dimensions automatically get changed. The most important incentive for the current web sphere is SEO (Search Engine Optimization) which is dramatically & automatically mended when DIV based layout is used where TABLE based layout is toilsome for search bots to crawl & takes much page loading time. And at some point it makes more sense to use table for displaying tabular formatted data only, for example gmail uses table for the email list, this could be done using UL/LI, but table is more appropriate in this case.
Lately most web designers use DIV for page layout designing for its flexibility and robustness. Unlike table div has a big problem (in fact it’s the nature of div) when you want to give same height to multi-columns div based page layout, you can not do that very easily. I always used javascript for this purpose, but wished if I could do it with css, cos when the javascript is disabled the page layout will be not as expected in most of the cases.
Yes it is possible to create equal height columns with css! You can make the height of multiple floated divs equal using CSS only and no javascript or invalid css. Before beginning I assume you have adequate knowledge on HTML, CSS, javascript and you have already Firebug add-on installed on your Firefox :)
Lemme start from the beginning:
When you apply float left and fixed width to multiple adjacent divs, by default the layout looks like the above screen shot. You can see it from browser or have a look at the source code (html/css) on the following link above. You see as the contents are not same in the 3 divs, the height is different.
The next example is making the height of the 3 divs same using javascript (jQuery).
This is mostly and widely used for making equal height columns using javascript. I’ve used jQuery here. You may have a look at the source code from the link above.
$(function(){
var H = 0;
$("div").each(function(i){
var h = $("div").eq(i).height();
if(h > H) H = h;
});
$("div").height(H);
});
Now here comes the css equal height technique! The mantra is to use a large amount of bottom padding and the same amount of negative bottom margin to the floated divs and keep them inside an overflow hidden div. That’s all, and the magic happens!
Let me get into details on how to do it. At First have a look at this link. Here I’ve used a huge amount (9000px) of bottom padding and the same amount of negative bottom margin (-9000px). But this makes the columns look so long and still not equal height at bottom. Now on this link I’ve used a holder div with overflow:hidden and that’s it, it is doing the magic by hiding the overflow section.
body{margin-bottom:50px}
div.holder { overflow:hidden }
div.holder div { float:left; width:30%; background-color:#9C0; margin-right:5px; padding:10px; padding-bottom:9000px; margin-bottom:-9000px }
Hope it’s clear now.
There is another method which use a background image with 1px height and color matched with the div’s bg color and body’s bg color. Please have a look at the html link, it’s self-explanatory.
Now I’ll try border to the columns and we’ll see the problem and it’s solution.
Here you can see bottom border is missing which is obvious as we’ve used a huge bottom padding, from Firebug if you turn off overflow:hidden to the holder div and scroll down at the bottom of the page you’ll see the bottom border there but not equal height.
So how to solve this issue? There are 2 ways to do it – using a bg image in a tricky way or another pure tricky css hack.
Here I’ve used a 1px bg image for the background image and placed it at left-bottom of the bottom-border div with no-repeat and also applied 1px bottom padding. The holder div is inside the bottom-border div. Please feel free to play around with firebug!
This is the last method for bottom border fix without any bg image, just pure css.
I’m not gonna explain the details of this last method, find it out yourself! :)
I worked a lot with drop-down menus like most of you. There are many stable versions of DD menus using pure javascript & CSS or only CSS with cross-browser support and you’ll get them free from many menu maker websites or desktop applications. So I’m not going to reinvent the wheel.
I’m a freaking fan of jQuery and always use it for drop-down menus with my custom jQuery code. It’s a must to use a delay for javascript driven dd menus even for jQuery when you want to give it some effect like slideDown or slideUp (For CSS dropdown menus it’s not possible & thus no need to use delay). I always wished to use jQuery without any setTimeout function for the drop-down menus. And I did it which I’m gonna share with you.
$(function () {
$("ul>li").hover(function () {
$(this).find("ul.sub").slideDown('fast');
$(this).addClass("hover");
$(this).hover(
function () {},
function () {
$(this).find("ul.sub").slideUp('fast');
});
},
function () {
$(this).removeClass("hover");
})
})
The main tricky part is using hover inside hover function:
$(this).hover(
function () {},
function () {
$(this).find("ul.sub").slideUp('fast');
});
This removes the mouseover function (first function of hover) when mouse hover into the li so the slideDown does not happen again when the mouse enter into the inner ul/li. Hope that makes sense. You may like to add a delay and do some more fine tunes.
Happy Coding!
On my another post I mentioned that cycle is a great jQuery plugin. I use it very often for slideshow. Recently I used it on a project where the slideshow had many(20+) wallpaper sized images. So loading time was a great issue.
The default cycle integration includes all the images during page loading which is okay for small images, but highly affects the page loading time for high resolution images. cycle plugin is highly flexible! I fixed the issue by loading images dynamically one after another at the end of each slide, literally before the beginning of each slide.
Here is how I did it:
<div id="slideshow"><!-- slides will be added here --></div>
var gallery = ["images/1.jpg", "images/2.jpg", "images/3.jpg", "images/4.jpg", "images/5.jpg", "images/6.jpg", "images/7.jpg", "images/8.jpg", "images/9.jpg", "images/10.jpg", "images/11.jpg", "images/12.jpg", "images/13.jpg", "images/14.jpg"]; // and so on.. array of images
// Array clone function.
Array.prototype.clone = function () {
var arr = new Array();
for (var property in this) {
arr[property] = typeof(this[property]) == 'object' ? this[property].clone() : this[property];
}
return arr;
}
var gal = null; // gal should be global as I'll use it inside onBefore function
$(function () {
gal = gallery.clone(); // cloning the array is not mandatory, but doing so will keep the main array unchanged.
$('#slideshow').empty().append('<img src="' + gal.pop() + '" /><img src="' + gal.shift() + '" /><img src="' + gal.shift() + '" />') // adding the last, first and second element of the array to the slideshow div, then start the cycle plugin.
.cycle({
startingSlide: 1,
// this is required (1 is the 2nd slide) as the first slide is the last element of the array. if you use manual next/prev button clicking on #prev will show the first element.
before: onBefore, // loads the next image at the beginning of each slide. (NOT all at once)
next: "#next",
prev: "#prev"
});
var totalSlideCount = 1 + gal.length;
function onBefore(curr, next, opts, fwd){
// at first addSlide is not defined, so we should return.
if (!opts.addSlide) return;
// if all the elements of the array are added no need to add them again!
if (opts.slideCount == totalSlideCount) return;
// shift or pop from slide array
var nextSlideSrc = fwd ? gal.shift() : gal.pop();
// add next slide
opts.addSlide('<img src="' + nextSlideSrc + '" />', fwd == false);
}
});
In this code above, cloning the array is optional. I used it as I needed the main array for later use. Probably you know if you use the global array reference to a local variable and apply pop()/shift()/push() functions to the local variable, the global one will be affected. cos the local variable is just a reference to the address of the global array variable.
At first the last, 1st and 2nd elements of the array are added to the #slideshow div and the cycle is started from the 2nd slide. Before starting of each slide onBefore function is called. The onBefore function adds new slide to the slideshow and stops when all the array elements are added to the slide.
You may use it for small size images also if you need to improve the page loading duration.
You can easily print google map from maps.google.com. But what about printing the map from gmap api you use on your own website? One way is to print the whole page which is not a good idea. Users want to print only the location of your business in a larger size for later purposes. Google map api does not provide any function to print the map or view it in printer friendly mode.
The only solution I found is using a simple javascript code for this purpose. At first place an image/text/button anywhere (obviously easily available to visitors) on the page that contains your map api. I prefer to use a small printer icon image. Apply onclick(inline or unobtrusive) event to the button to popup a page say print.html.
<img src="images/print.png" class="print" alt="print" title="print" onclick="window.open('print.html')" />
Now create an empty html document, name it print.html and put it in the root folder of your site. Place this simple javascript code inside body tag of print.html
<script language="javascript">
var contents = window.opener.document.getElementById("map_container");
document.write(contents.innerHTML);
window.print();
</script>
Replace the “map_container” with the #id you are using for your map container. That’s all, you are done!
This method is good enough for printing static google map layout. But you can not print driving direction as that line is drawn using canvas element. In fact you can not print the exact driving direction even from maps.google.com.
This is more or less a better solution for printing the map from your own website’s gmap api. Please lemme know if you know any smarter way to do it.
IE6 sux. General css/javascript hover drop-down menu uses a div or ul with position:absolute. No matter how much you increase the value of z-index the select box (windowed element) will always remain on top most – yes only on a special browser, Internet Explorer 6. The reason is IE6 considers select element as windowed element and keeps it always on top layer.
Solution is using iframe on top of select element, as iframe is also a windowed element placing it on top of select box fix the problem.
Here is the typical HTML code for this drop-down menu:
<div class="top-menus" style="left: 221px; top: 127px;">
<iframe frameborder="0" scrolling="no" align="bottom" marginheight="0" marginwidth="0" src="javascript:'';" style="height: 200px;"></iframe>
<ul>
<li><a href="#">Bracelets</a></li>
<li><a href="#">Rings</a></li>
<li><a href="#">Earrings</a></li>
<li><a href="#">Necklaces</a></li>
</ul>
</div>
The inline css is calculated using jQuery offset() function. FYI, you can easily get the width,height,left,top position of any element using jQuery(“element”).offset(). Make sure the width and height of the iframe is exactly same of it’s overlying UL element. If you apply any border to the UL, you have to consider that during calculating the proper width/height of the iframe.
This is the sample jQuery code:
var timer = null; // global
$("#top-nav a").hover(function(){
clearTimeout(timer);
$("#top-nav a:not('.cur')").removeClass("selected");
$(this).addClass("selected");
var o = $(this).offset();
var left = o.left + 1; // 1px extra for border
var top = o.top + 32; // 32px for placing it just below the horizontal menu
if($(".top-menus").length){
if(left == $(".top-menus").offset().left)
return;
else $(".top-menus").remove();
}
$("body").prepend('<div style="left:'+left+'px;top:'+top+'px;" class="top-menus"><iframe src="javascript:\'\';" marginwidth="0" marginheight="0" align="bottom" scrolling="no" frameborder="0"></iframe><ul>'+html+'</ul></div>');
$(".top-menus").find(".parent, .child").remove();
var hi = $(".top-menus").find("ul").height();
$("iframe").height(hi + 2); // extra 2px for border
}, function(){
clearTimeout(timer);
timer = setTimeout(function(){$("body").find("iframe,.top-menus").remove(); $("#top-nav a:not('.cur')").removeClass("selected");},300);
});
$(".top-menus").live("mouseover",function(){
clearTimeout(timer);
}).live("mouseout",function(){
clearTimeout(timer);
timer = setTimeout(function(){$("body").find("iframe,.top-menus").remove(); $("#top-nav a:not('.cur')").removeClass("selected");},300);
});
I know this code won’t exactly fulfill your requirement, you can get the main idea from this and write your own code yourself. You can see it in action on www.trendtogo.com.
I’m basically a jQuery developer. I had little knowledge about prototype.js. All I knew is jQuery is better than prototype, so I never got interested about it.
However, for some reason I started a project with prototype.js and each line of code makes it clearer that which one is better. Somehow I finished the project using prototype.js along with scriptaculous.js and effects.js. Everything was fine in IE7 and FF 3. But it breaks in IE6. I was not happy with the unnecessary huge code. For example there is no live event in prototype.js, you can not apply an event to a group of elements with same class (You have to use loop for it), there is nothing like jQuery.animate function by which you can do any css animation (You have to add scriptaculous.js for some pre-built animation effects!) and a lot more limitations.
Even the scriptaculous.js is not that rich, for example using ScrollTo effect you can smoothly scroll to any anchor tag “vertically” only but no way of ScrollTo horizontally(!) in case your page is landscape orianted. Here is the code that I used instead(I found the idea from the source code of ScrollTo function):
var scrollOffsets = document.viewport.getScrollOffsets();
var elementOffsets = $$('div.active ul li')[index].cumulativeOffset();
new Effect.Tween(null,scrollOffsets.left,elementOffsets[0] - lo,function(p){window.scrollTo(p,scrollOffsets.top);});
The equivalend jQuery code is:
$("html,body").animate({
scrollLeft: ($('div.active ul li').eq(index).offset().left - leftOffset) + 'px'
}, "slow", "swing");
There are a lot more examples like this. The summary is the code using prototype.js was 180 lines and the equivalent code using jQuery is now only 160 lines + a lot of mental relief that it would work on all browsers :)
One thing I want to make clear is I have no intention to boost anything. In fact both of them are free.
Once I needed to get maximum z-index of a DIV to show message at the top of the screen.
Usually, I used arbitrary z-index of 100 of the DIV. But that one is not at the top and it’s hidden by others.
What’s wrong? And unfortunately I found that there are 3 more div-s which have z-index attribute which are greater than 100.
So I changed the z-index to 1000. This time I can see one portion of the DIV.
But 2 more elements get the desired message container DIV overlaid. Frustrating! Huh!
Trial and error method always makes you delay.
I know JavaScript or jQuery may get rid of this hell.
I made an absolute tinny code to find the highest z-index of absolute DIV
to show my shouting box and to make it appear absolutely at the top of all html elements.
//include jQuery.js -- visit: http://jquery.com/
$(function(){
var maxZ = Math.max.apply(null,$.map($('body > *'), function(e,n){
if($(e).css('position')=='absolute')
return parseInt($(e).css('z-index'))||1 ;
})
);
alert(maxZ);
});
I used selector of ”body > *‘ instead of ‘body *‘.
”body > *‘ means all tags/elements which are found at first depth of
whether ”body *‘ selects all tags/elements at any depth.
It doesn’t matter what’s is the maximum/highest z-index of an absolute element
rather it matters what’s the maximum/highest z-index of the absolute elements
which are next to in first depth only to show the shouting box on top most strata.
N.B. Shouting box is appended to document.body in this case.
It is very simple to get the current windows username in PHP. The following one line of code will output the username of the system where the server is running. If you are running this from localhost then your system login name will be shown. But you can not get the visitor’s system login username.
<?php echo getenv("username"); ?>
By using javascript (actually VBscript) you can get the visitor’s windows username. But there are also limitations. It only works on IE.
<script language="VBscript">
Dim X
set X = createobject("WSCRIPT.Network")
dim U
U=x.UserName
MsgBox "username: " & U
</script>
<script language="Javascript">
var a = U;
alert("Hello, " + a.toString());
</script>
This code will show you the current windows username. But won’t work if run from http://. Open the page from your computer with IE and it’ll work, otherwise not.
Actually it is not possible to get the windows username of your website visitors as it is a security issue. So don’t waste your time if you are trying to do that.
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