Tech Thought

Tech tips, hints, and general musings. PHP, Perl, Mysql, Javascript, AJAX, JSON, Linux, Mac OSX

Entries Tagged ‘javascript’

How-To: Redirect to different URL using Javascript or META tags

Aug.18, 2008 in Development, How To

If you need to redirect from one page to another, you can achieve this with either a META tag redirection or Javascript.  See below for an example.  You should provide a manual link as not all browsers support META tags - and javascript won’t work if its been disabled:
<html>
<head>
<title>Move my domain!</title>
<meta http-equiv=”refresh” content=”url=http://www.newdomain.com”>
<script language=”JavaScript”>
function Redirect()
{
window.location [...]

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FusionCharts Fix: Stop charts appearing in front of modal dialog or html elements

Mar.26, 2008 in Development

We have been using Fusion Charts for a number of projects. They provide very nice slick looking animated graphs and widgets (now available as Google Gadgets too incidentally). However as they are Flash based they can cause problems when you place other elements in front of them - for example a “modal dialog” [...]

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ModalBox: Modal Dialog Boxes Based on Prototype.js

Mar.07, 2008 in Development

If you’ve ever used the Sustainability Victoria calculator, Administered Joomla or poked someone on Facebook, then you might wonder how they create those nice modal dialog boxes that have replaced the ugly javascript confirm() in most modern web applications:

Well, thanks to prototype.js and ModalBox now you can. ModalBox is a javascript library that helps you [...]

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How-To: Speed up page loading - compressed prototype.js

Mar.06, 2008 in Development

To help speed up the load time of your prototype.js and scriptaculous pages, you can now download fully compressed versions of all the required files from the ‘prototype-core’ group on google thanks to John David-Dalton (original post on Ajaxian):
http://groups.google.com/group/prototype-core
This reduces the size of prototype and scriptaculous to 64k total! Be sure to [...]

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Javascript OO: Scope of ‘this’ variable when using prototype.js

Mar.06, 2008 in Development

If you write a fair bit of OO javascript and also utilise AJAX through one of the many frameworks (I personally use prototype.js most of the time) you may have come across the following issue:

var myobj = new Object();

myobj.Methods = {
result: 0,
callAjax: function() {
[...]

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How-To: Debugging Javascript in IE with Microsoft Script Debugger

Feb.27, 2008 in Development

Debugging javascript in IE is often like walking on a minefield with a blindfold on. You have no idea where you are when bombs go off. Thankfully, Microsoft provides a debugging tool called Microsoft Script Debugger which makes debugging javascript much easier. You can download the tool from here.

Once installed you get [...]

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URL Encoding a string with javascript

Feb.26, 2008 in Development

The following javascript function returns a URL encoded string so that it is safe to use in URLs or as a GET request:
function URLDecode (encodedString) {
var output = encodedString;
var binVal, thisString;
var myregexp = /(%[^%]{2})/;
while ((match = myregexp.exec(output)) != null
[...]

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How-To: Capture ‘return key’ from a field with Protoype.js

Feb.25, 2008 in Tech

Prototype provides an excellent abstraction mechanism for event handling in javascript. I needed to capture when a user hit the ‘return key’ inside a text box, and then perform a specified action. Using the observe function and the KEY_RETURN constant, you can easily detect when this is done.
Simply place the following [...]

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Typecasting Strings to Numbers in Javascript

Feb.11, 2008 in Development

If you are using the values on a page (e.g. the values of form elements) directly in mathematical formulas in javascript, you can have issues with ambiguity of types. For instance:

var total = 0;
total += document.myForm.element.value; // e.g. value = 5
alert(total);
The [...]

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Javascript validation of Email Address, Numeric Values and an Input Mask for Numbers Only

Feb.05, 2008 in Development

A couple of very simple yet handy routines for validation of form fields:
Function to validate an email address (see original post):

function ValidateEmail(email){
var emailReg = “^[\\w-_\.]*[\\w-_\.]\@[\\w]\.+[\\w]+[\\w]$”;
var regex = new RegExp(emailReg);
return regex.test(email);
}
Function to validate a number:

function ValidateNumber(num)
{
return num.match(/^\d+$/);
}
Input mask for [...]

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Creating Objects with Javascript

Feb.05, 2008 in Development

Recently I’ve started overhauling all our old javascript libraries to make them more object-based and easier to maintain. As a result, I’ve needed to get familiar with how to create objects and assign properties and methods. This is surprisingly easy in javascript:
Creating an object (Constructor) with properties:

function MyObject(param1, param2)
{
this.myProperty [...]

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Debugging objects in Javascript with prototype.js

Jan.21, 2008 in Tech

Often when coding complex javascript you’ll wish you had the ability to debug objects or arrays that you are working on - much like Data::Dumper in Perl or var_dump in php (see previous posts on these topics). Prototype.js provides an easy way to do this using the .inspect() method for hashes and arrays:

var [...]

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“Foreach” style loop syntax for Perl, Php and Javascript

Jan.21, 2008 in Development

I am always forgetting the syntax for foreach() loops in javascript. They actually don’t exist (not in their Perl or Php form anyway) and they differ in that they iterate over all the properties of an object, not an array. You can get some unexpected results if you aren’t careful.
In perl you do [...]

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Welcome

Welcome to Ev's Tech Thought of the Day. Here you'll find hints and tips that I've found throughout my travels and thought worthy to share with the world. Enjoy!