Posts Tagged JavaScript
Round Number upto 2 decimal places in JavaScript
Posted by admin in JavaScript on January 17th, 2010
JavaScript’s Math.round() function doesn’t provide facility to round off a number up to 2 or more decimal places. So, here I’m showing a simple JavaScript code using which you can round off numbers up to 2 decimal places. You can change this for more decimal places.
var retailPrice = 9.99; var percentage = 0.2525; /* 25.25% */ var decimalPlace = 100; /* 100 for 2 decimal place. 1000 for 3 decimal place.*/ var wholeSalePrice = Math.round(percentage * retailPrice * decimalPlace) / decimalPlace; alert(wholeSalePrice); /* This will show 2.52 */
Initialize LightBox using JSON string and Run it from Flash
Posted by admin in Flash, JavaScript, Prototype on August 25th, 2009
Lightbox is the most popular way of showing large image on click on thumbnail over the web. Lot of websites are using the LightBox. Normally, We use lightbox using the “rel” attribute of anchor tag. We use lightbox this way:-
<a href="images/image-1.jpg" rel="lightbox" title="thumb"><img src="images/thumb-1.jpg" width="100" height="40" alt="" /></a>Here, we provided the “rel” attribute as “lightbox” in hyperlink. What lightbox script do is when page load completed its check all the hyperlinks of page and if rel=”lightbox” is exists them it push this link into an array.
Lightbox extract the “href” and “title” attributes of each link having rel=”lightbox” and push all of them into array. “href” is normally the URL of larger image. Lingtbox also add “click” event on all of these hyperlinks and when user click on any particular thumbnail the lightbox starts.
Here, I’m showing a way in which you can initialize the lightbox by using the JSON string. Basically, this JSON string contains the “href” and “title” information which we want to show. We can create this string dynamically using any server side scripting language. Here is one of sample JSON string.
<script language="javascript"> var img_json = [['pics/photo-80.jpg', 'Title 01'],['pics/photo-128.jpg', 'Title 02'],['pics/photo-160.jpg', 'Title 03'],['pics/photo-165.jpg', 'Title 04'],['pics/photo-205.jpg', 'Title 05'],['pics/photo-206.jpg', 'Title 06']]; </script>
You can learn more about JSON here.
We also need to do some small changes in lightbox javascript file so it use our JSON string for image array instead of create array by checking the “rel” attribute in whole page.
You can download the customized lightbox javascript file from here.
You can see the working demo here.
1. Remove the “imageLink” parameter from start function because now we not starting LightBox by not clicking any thumbnail.
start: function(imageLink)
function to
start: function()
2. Now we are initializing the “imageArray” using JSON string.
this.imageArray = [];
to
this.imageArray = img_json;
3. Comment these line of code inside start function bacause we not want to check whole page links for lightbox.
/*if ((imageLink.rel == 'lightbox')){
// if image is NOT part of a set, add single image to imageArray
this.imageArray.push([imageLink.href, imageLink.title]);
} else {
// if image is part of a set..
this.imageArray =
$$(imageLink.tagName + '[href][rel="' + imageLink.rel + '"]').
collect(function(anchor){ return [anchor.href, anchor.title]; }).
uniq();
while (this.imageArray[imageNum][0] != imageLink.href) { imageNum++; }
}*/4. Add function startLightBox() at the end of Lightbox class. This function start the lightbox when we click on the link having id=”start”.
startLightBox: function() { var th = this; Event.observe($('start'), 'click', function () { th.start(); }); }
5. Add this line in initialize() function to call “startLightBox()” function which create the click event on link having id=”start”.
this.startLightBox();
After completing all the five changes in lightbox.js you need to create a link with id = “start” in your HTML file. When you click on this link its starts the LightBox. Here is the code for HTML file.
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Initialize LightBox using JSON string and Run it from Flash</title> <link rel="stylesheet" href="css/lightbox.css" type="text/css" media="screen" /> <script src="js/prototype.js" type="text/javascript"></script> <script src="js/scriptaculous.js?load=effects,builder" type="text/javascript"></script> <script src="js/lightbox.js" type="text/javascript"></script> </head> <body> <a href="#" id="start">Start LightBox</a> </body> <script language="javascript"> var img_json = [['pics/photo-80.jpg', 'Title 01'],['pics/photo-128.jpg', 'Title 02'],['pics/photo-160.jpg', 'Title 03'],['pics/photo-165.jpg', 'Title 04'],['pics/photo-205.jpg', 'Title 05'],['pics/photo-206.jpg', 'Title 06']]; </script> </html>
Unscape HTML in JavaScript
Posted by admin in JavaScript on July 13th, 2009
This function strips tags and converts the entity forms of special HTML characters to their normal form. I created this function with the help of code of Prototype JavaScript library.
<script language="javascript"> function unscapeHTML(str) { var div = document.createElement('div'); div.innerHTML = str.replace(/<\/?[^>]+>/gi, ''); if (div.childNodes[0]) { if (div.childNodes.length > 1) { var retStr; for (var i = 0; i < div.childNodes.length; i++) { retStr += div.childNodes[i].nodeValue; } return retStr; } else { return div.childNodes[0].nodeValue; } } else { return ''; } } </script>
How you can use it.
<script language="javascript"> var1 = 'x > 10'; alert(unscapeHTML(var1)); // This will alert 'x > 10' var2 = '<h1>Pride & Prejudice</h1>'; alert(unscapeHTML(var2)); // This will alert 'Pride & Prejudice' </script>
Show image when its completely received by browser
Posted by admin in HTML, JavaScript, jQuery on May 17th, 2009
In this example, I am showing how to display image when its completely received by browser. We need this kind of thing when we are changing any Image through JavaScript and want to show some loader until image is not completely receive by client browser. I am using Image onload event for this purpose. Its fires when image is load by browser. When user click on prev or next link we hide the image by adding the ‘hide‘ class to ‘<img>‘. So, user will see the loader image which we placed in the background of image container. When browser load the next image we removed the ‘hide‘ class from ‘<img>‘ and changed its ‘src‘ from older image to new image. I am also using jQuery for adding and removing CSS class from HTML Element. Check out the Javascript, CSS and HTML code below.
HTML Code:-
<div class="container"> <div class="prev"><a id="prev" href="javascript:void(0);">«Prev</a></div> <div class="image-container"><img id="pic" src="img/blank.jpg" class="hide" /></div> <div class="next"><a id="next" href="javascript:void(0);">Next»</a></div> <div class="clear-float"></div> </div>
CSS Code:-
<style type="text/css" media="screen"> * { margin:0; padding:0; border:0; font-family:Arial, Helvetica, sans-serif; font-size:1em; font-weight:normal; font-style:normal; text-decoration:none; color:#666; } .container { width:800px; margin-left:auto; margin-right:auto; } .image-container { height:300px; width:400px; border:#333333 thin dashed; margin-top:100px; background:url(img/indicator2.gif) center no-repeat; float:left; } .image-container img { height:300px; width:400px; } .prev{ width:50px; float:left; margin-left:143px; margin-top:250px; } .next{ width:50px; float:left; margin-top:250px; text-align:right; } .clear-float { clear:both; height:1px;} .hide { display:none;} </style>
JavaScript Code:-
<script type="text/javascript" src="img/jquery.js"></script> <script language="javascript"> $(document).ready(function() { var index = 0; var path = 'img/'; var images = ["1.jpg", "2.jpg", "3.jpg", "4.jpg", "5.jpg", "6.jpg", "7.jpg", "8.jpg", "9.jpg", "10.jpg"]; var pre_images = new Array(); var loaded = new Array(); $("#prev").click(function() { index--; $("#pic").addClass('hide'); if (index < 0) {index = images.length - 1} getImage(); }); $("#next").click(function() { index++; $("#pic").addClass('hide'); if (index >= images.length) {index = 0} getImage(); }); function getImage() { if (loaded[index] == true) { document.getElementById("pic").src = pre_images[index].src; $("#pic").removeClass('hide'); } else { pre_images[index] = new Image(); pre_images[index].src = path + images[index]; pre_images[index].onload = function() { loaded[index] = true; document.getElementById("pic").src = pre_images[index].src; $("#pic").removeClass('hide'); } } } getImage(); }); </script>

