A K Chauhan's Blog » JavaScript

How know Base Path of Drupal in JavaScript

admin — Mon, 17 May 2010 10:45:54 +0000

Sometimes you want to know about the Base Path of your Drupal installation in JavaScript. You may want to know about this path for sending the AJAX request at correct URL relatively, load the image or some other type of file on client side through JavaScript etc.

Drupal provide a variable called Drupal.settings.basePath for this purpose in JavaScript. But this variable is only available if you include any custom JavaScript file or JavaScript block in your module. By default Drupal doesn’t include the ‘jquery.js‘ and ‘drupal.js‘ file in generated output. It only add these files if you add your custom JavaScript file or JavaScript block. We can include our custom JavaScript file in Drupal like this:-

drupal_add_js(drupal_get_path('module','my_module'). '/my_module.js');

The my_module.js file should reside in same directory where my_module module exist. This will force Drupal to add jquery.js and drupal.js files in output.

These two files initialize the Base Path variable. In drupal.js file, on top you can see the initialization of setting object in Drupal object. Like this:-

var Drupal = Drupal || { 'settings': {}, 'behaviors': {}, 'themes': {}, 'locale': {} };

Drupal generate some JavaScript code in Script block inside head tag of each page for extending the settings object with the help of jQuery. Like this:-

jQuery.extend(Drupal.settings, { "basePath": "/" });

You can test the Base Path by adding following code in my_module.js file.

$(document).ready(function() {
	alert(Drupal.settings.basePath);
});

This will alert the Base Path for Drupal installation after loading of the page.

Round Number upto 2 decimal places in JavaScript

admin — Sat, 16 Jan 2010 22:41:33 +0000

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 */

JavaScript List Search using jQuery

admin — Thu, 29 Oct 2009 20:58:27 +0000

List Search using jQuery

Here in this example we are using jQuery to filter the list of products. We have list of products in UL and LI. We have associated the “KeyUp” event on the top search textbox. So when somebody type in the textbox we filter the list on the basis of entered value.

We are using the RegExp for comparing the string for matching characters. First we created the regular expression “rg” from the given text and compare the product name (string) with the help of search function.

The search function return the position of string where match is found or ‘-1′ in case of no match.

So, we selected all the LI’s exist inside the ‘product_list‘ ID and match each product name one by one. We hide the LI if its text not match the current search text and display the LIs with matching text.

HTML Code: -


<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Sales Vu</title>
<link rel="stylesheet" href="pm-common-new.css" type="text/css" />

</head>
<body style="padding-left:20px;">
<div class="top-bar">
    <div class="top-left-corner"><img src="images/top-left-corner.png" /></div>
    <div class="top-mid-bg">Product Management</div>
    <div class="top-right-corner"><img src="images/top-right-corner.png" /></div>
</div>
<div class="body-part">
    <div class="body-part-top">
        <div class="search-container">
            <div class="search-box" style="float:left; width:257px;">
                <div style="float: left; width: 70px; padding-top: 4px; font-weight: bold;">Search </div> 
                <div class="text-field-box">
                    <input name="" type="text"  id="search" autocomplete="off" class="search-box-bg" />
                </div>
                <div class="text-field-cancel-button">
                    <a href="javascript:void(0);" id="search_clear" ><img src="images/search-box-cancel.png" border="0" id="search_clear" /></a>
                </div>
            </div>
        </div>
        <div class="modifier-product">
            <div class="modifier-product-right" style="float:left;">
                <div class="modifier-product-right-top">
                    Product
                </div>
                <div class="modifier-product-right-mid">
                    <div class="modifier-product-right-detail" id="product_list">
                        <div class="modifier-product-right-detail-heading">
                            <div class="product-list-heading">Product</div>
                            <div class="price-list-heading">Price ($)</div>
                        </div>
                        <div class="product-list">
                            <ul>
                            	<li>
                                    <div class="product">Banana Split</div>
                                    <div class="price">3.00</div>
                                </li>
                                <li>
                                    <div class="product">Bird Lite</div>
                                    <div class="price">2.45</div>
                                </li>
                                <li>
                                    <div class="product">Butter</div>
                                    <div class="price">2.00</div>
                                </li>
                                <li>
                                    <div class="product">Chicken With Coke</div>
                                    <div class="price">3.45</div>
                                </li>
                                <li>
                                    <div class="product">Chips With Coke</div>
                                    <div class="price">3.75</div>
                                </li>
                                <li>
                                    <div class="product">Corono Lite</div>
                                    <div class="price">2.00</div>
                                </li>
                                <li>
                                    <div class="product">Eggs</div>
                                    <div class="price">0.50</div>
                                </li>
                                <li>
                                    <div class="product">Limca</div>
                                    <div class="price">1.05</div>
                                </li>
                                <li>
                                    <div class="product">Sprite</div>
                                    <div class="price">1.20</div>
                                </li>
                                <li>
                                    <div class="product">test product</div>
                                    <div class="price">3.00</div>
                                </li>
                            </ul>
                        </div>
                    </div>
                </div>
                <div class="modifier-product-right-bottom">
                     
                </div>
            </div>
        </div>
    </div>
    <div class="body-part-bottom">
        <img src="images/body-bottom.png" />
    </div>
    </div>
</body>
</html>
<script src="jquery.js" type="text/javascript"></script>
<script src="pm_new.js" type="text/javascript"></script>

JavaScript Code: -

// JavaScript Document
$(document).ready(function () {
	$('#search').keyup(function(event) {
		var search_text = $('#search').val();
		var rg = new RegExp(search_text,'i');
		$('#product_list .product-list .product').each(function(){
 			if($.trim($(this).html()).search(rg) == -1) {
				$(this).parent().css('display', 'none');
 				$(this).css('display', 'none');
				$(this).next().css('display', 'none');
				$(this).next().next().css('display', 'none');
			}	
			else {
				$(this).parent().css('display', '');
				$(this).css('display', '');
				$(this).next().css('display', '');
				$(this).next().next().css('display', '');
			}
		});
	});
});
 
$('#search_clear').click(function() {
	$('#search').val('');	
 
	$('#product_list .product-list .product').each(function(){
		$(this).parent().css('display', '');
		$(this).css('display', '');
		$(this).next().css('display', '');
		$(this).next().next().css('display', '');
	});
});

Initialize LightBox using JSON string and Run it from Flash

admin — Tue, 25 Aug 2009 06:19:50 +0000

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 = [];

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

admin — Mon, 13 Jul 2009 07:03:44 +0000

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 = 'Pride & Prejudice
';
alert(unscapeHTML(var2));
// This will alert 'Pride & Prejudice'
script>

Show image when its completely received by browser

admin — Sun, 17 May 2009 12:54:23 +0000

Click on Image to see demo

See demo here

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 ‘‘. 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 ‘‘ 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:-