Random Snippets

function calculatePercentage (oldval, newval) {
percentsavings = ((oldval – newval) / oldval) * 100;
document.getElementById(“results”).innerHTML = Math.round(percentsavings*100)/100;
}

Here is a simple JavaScript function that does dynamic or on-the-fly percentage calculations.

Demo
MSRP (in dollars)

Sale Price (in dollars)

You have saved 50 %

I recent ran into an interesting IE bug involving the following bit of html code:

<a href="javascript: void(0);" onclick="dosomething();">click me</a>

I honestly did not write this one but I will leave names out of this to protect the innocent =)
The void(0) JavaScript code is usually used to prevent loading or reloading of the page when the user [...]

function removeYellowBox() {
var parentBox = document.getElementById(‘parentBox’);
var yellowBox = document.getElementById(‘yellowBox’);
parentBox.removeChild(yellowBox);
}

JavaScript has a built-in function called confirm which takes a string argument that poses the question to the user and gives them the option to click the OK or Cancel buttons and returns true if [...]

function findParentNode(parentName, childObj) {
var testObj = childObj.parentNode;
var count = 1;
while(testObj.getAttribute(‘name’) != parentName) {
alert(‘My name is ‘ + testObj.getAttribute(‘name’) + ‘. Let\’s try moving up one level to see what we get.’);
[...]

function loopForm(form) {
var cbResults = ‘Checkboxes: ‘;
var radioResults = ‘Radio buttons: ‘;
for (var i = 0; i < form.elements.length; i++ ) {
if (form.elements[i].type == ‘checkbox’) {
[...]

function calculate(equation) {
var answer = eval(equation);
document.getElementById(’screen’).value = answer;
}
function pushButton(buttonValue) {
if (buttonValue == ‘C’) {
document.getElementById(’screen’).value = ”;
}
else {
[...]

function addContent(divName, content) {
document.getElementById(divName).innerHTML = content;
}
function setCookie(c_name,value,expiredays) {
var exdate=new Date();
exdate.setDate(exdate.getDate()+expiredays);
document.cookie=c_name+ “=” +escape(value)+((expiredays==null) ? “” : “;expires=”+exdate.toGMTString());
}
function getCookie(c_name) {
if (document.cookie.length>0) {
c_start=document.cookie.indexOf(c_name + “=”);
[...]

This JavaScript demo verifies that an email address is in the correct format and that the user has typed in the same address in both fields to prevent mistyping of the address. I have borrowed the regex for verifying the correct email format from a different site.

Demo

Email:

Please type in your email again:

function removeElement(parentDiv, childDiv){
if (childDiv == parentDiv) {
alert(“The parent div cannot be removed.”);
}
else if (document.getElementById(childDiv)) {
var [...]

This is a neat little script that demonstrates two things:
1) Find – If only the Find box is filled in, then the findMyText() JavaScript function will just perform a find for the div that is given. If there is a match, the text will be highlighted and marked in bold.
2) Find and Replace – [...]

There is a rare need for this type of functionality but I have found myself in a couple of situations where I needed it. Here is a quick demo of a button click that is simulated from another event handler. In this case, the button click is invoked by checking a checkbox.

Demo
Check the [...]

function selectToggle(toggle, form) {
var myForm = document.forms[form];
for( var i=0; i < myForm.length; i++ ) {
if(toggle) {
myForm.elements[i].checked = “checked”;
[...]

function verifyForm(form) {
var userName = form.name.value;
var userEmail = form.email.value;
var success = 1;
if (!userName) {
document.getElementById(“usernameMsg”).style.display = “”;
form.name.style.backgroundColor = “yellow”;
[...]

The Document Object Model (DOM) allows for dynamic styling because it makes all HTML elements and attributes readily accessible using JavaScript. Here is a simple demo of how powerful this technology can be:

Demo
Hello world!

Not all forms are meant to be static. Sometimes, you want to allow the users to add certain parts of the form as they need them. Here is a nice example of dynamically adding inputs to your form as users need them. In addition, an input limit has been implemented in the [...]

Are you trying to find a way to hide and show your content? The demo below shows a simple yet elegant way of toggling your content and toggling the control text via Javascript and styling.

function toggle() {
var ele = document.getElementById(“toggleText”);
var text = document.getElementById(“displayText”);
if(ele.style.display == “block”) {
ele.style.display = “none”;
text.innerHTML = [...]

I have found myself in a couple of situations where I needed a simple dynamic javascript menu where the user would make a selection from one select list and depending on what the user selected from the first select list a second list would offer further options. Here is a perfect example:

Demo
Country:

Select country… [...]