I’m working on a project that uses the JScrollPane JQuery Plugin to scroll a number of records. My client wanted the scroll bar to have a variable height (like most modern scroll bars). The height of the scroll bar should be determined by the number of records – the height should decrease as the number of records increase. So the scroll bar height is inversely proportional to the number of records.
Archive for the ‘Javascript’ Category
While working on a project, I wanted to test whether a variable was undefined in Javascript. Because Firebug displayed ‘undefined’ in the console, I assumed that I could treat it as a string.
if (variable == 'undefined') { // do something } |
Now I knew that this wouldn’t work, but I tried it anyway. ‘undefined’ an object, not a string, so I could not treat it as a string.
After a minute of searching, I found the undefined solution:
if (typeof(variable) == 'undefined') { // do something } |
Using the typeof operator, Javascript is able to determine whether a variable/object is ‘undefined’.
When I upgraded my imGoogleMaps JQuery Plugin, I had to create a custom control button on the Google Map. The Control allows the user to add a Street View Overlay to the map. To create the control, I had to assign a prototype object to the instance of the GControl object.
I use Javascript Objects quite frequently when I am developing web applications. These objects are very flexible and are easy to create and easy to manipulate. In this post, I will discuss how I use Javascript Objects to store and retrieve application data.
I was trying to fill a dijit.form.combobox dynamically without using ItemFileReadStore, but it has proven to be quite a challenge. I was trying to fill the combobox from an array. It appears that Dojo’s combobox does not inherit all the attributes of a regular HTML combobox. When using just Javascript to dynamically fill a combobox, I made use of the ‘options’ attribute:
CSS, Javascript, Pebblet, YUI
In order get the height of a div in IE when the height is set to auto (or not set), use offsetHeight. I generally do not set the height of a div if I want the height to be determined by the the content inside the div. I was working on a YUI widget that is similar to my imAnimTabber JQuery plugin. I used YUI’s animation utility to display the tabbedd content. When using the animation object, you have to specify the attribute that is to animated and the value the attribute should be set to:
{height: {to: ‘100px ‘}}
Because the height of the divs for the tabbed widget is dependent upon the content, I do not know what the height of the content will be. To get the height of each div in Firefox, I simply called the getStyle Dom method (YUI):
YAHOO.util.Dom.getStyle(element, ‘height’);
Of course, IE returned ‘undefined’ as the height value. So, I first had to determine if the user was using ie and then use ie’s offsetHeight to determine the height:
if (YAHOO.env.ua.ie) {
var el = YAHOO.util.Dom.get('element');
var h = el.offsetHeight;
}
Since we know that Microsoft is not going to change ie, I hope that YUI will change their getStyle Dom method so that it can accommodate the various browser inconsistencies.
I have been trying to find a YUI method that is similar to the JQuery $.each method, but the closest thing I could find for the current version of YUI is YAHOO.util.Dom.batch (YUI 3 has an ‘each’ method, but I haven’t explored it thoroughly). While this method is not as powerful as JQuery’s $.each (see example), it is still a very good replacement for a Javascript ‘for’ loop when iterating over a DOM collection.
The JQuery $.each object accessor is probably the best method since the invention of the wheel (or at least, since Stargate SG1 was first conceived). It completely replaces the ‘for’ loop to iterate over an object. The power of this method is that it can iterate over any collection (Dom collections, associative arrays, JSON objects, etc). In general, using JQuery can make Javascript development so much easier.
The more I use the Yahoo User Interface Library (YUI), the more I am impressed with it. I have been converting my JQuery imValidateForm plugin to a YUI widget for a project that I am working on. I ran into a scope issue when a button was clicked. I have dealt with Javascript scope issues in the past, but I did not know how to fix it using YUI. Read the rest of this entry »
