A Quick Overview On JavaScript
JavaScript is used everywhere online these days – to improve website interactivity, to validate information, and/or to improve a website outlooks. JavaScript first appeared in 1995 and has come a long way since then in terms of being accepted and how it is used. The syntax used in JavaScript was strongly influenced by C; but Java, Pearl, Python, and Scheme also played its part too.
What Is JavaScript?
There’s an old YouTube clip answers the question well. Here goes.
Beginner Tips: What You Need To Know?
For starters, a few basics you need to know are:
- JavaScript can be turned off in the browser
- JavaScript will run each time a page is loaded
- JavaScript takes time to load on a slow Internet connection
- JavaScript is still ran from cached pages
- You can host JavaScript within a web page or externally from a .js file
- JavaScript is completely different than Java
It is also important to understand that JavaScript will actually lead to disaster when it’s used in a wrong way. Poorly configured and sloppy coded JavaScripts will slow your website and damage the overall site navigation. This in turn affect the return rate of your visitors (due to bad user experience) as well as search engine rankings (due to slow website response rates). To help validate my case here, put yourself in the shoes of a viewer. If a website you were visiting loaded slowly, was difficult to navigate, and in overall, unappealing – would you return to the site? I wouldn’t.
Below is a small list of things to think about when adding JavaScript to your website.
- Is JavaScript required for the site to function properly?
- What will the site look like if the JavaScript was blocked?
- Will the JavaScript harm the server performance?
- Will adding the JavaScript help move your site in the direction you want it to go?
No, I am not trying to scare you away with these points. In fact, don’t be afraid to use JavaScript on your websites as it provides tons benefits and, as mentioned, it’s used by the majorities. The key point I am trying to get across here is don’t just keep adding JavaScript features to a site when they are unnecessary. Some sites are will need more JavaScript than the rest; some just need less – Just because one site is doing it doesn’t mean you should do the same.
Freebies: 15 Cool JavaScript Snippets For Your Website
Now, let’s get down to the stuffs that you came here for – below is a list of 15 JavaScript snippets that will enhance your site in either functionality or appearance. The code will be broken down into two sections, the head and body or .js file. If no section title is given then it is not needed for that particular snippet.
Understanding HTML5 Video
Quick Sample
<script type="text/javascript">
function understands_video() {
return !!document.createElement(‘video’).canPlayType; // boolean
}if ( !understands_video() ) {
// Must be older browser or IE.
// Maybe do something like hide custom
// HTML5 controls. Or whatever…
videoControls.style.display = ‘none’;
}</script>
What does the JavaScript snippet do?
This little snippet will prevent your website from trying to display a video that the browser cannot support, saving you bandwidth and processing power.
JavaScript Cookies
Quick Sample
<script type="text/javascript">
/**
* Sets a Cookie with the given name and value.
*
* name Name of the cookie
* value Value of the cookie
* [expires] Expiration date of the cookie (default: end of current session)
* [path] Path where the cookie is valid (default: path of calling document)
* [domain] Domain where the cookie is valid
* (default: domain of calling document)
* [secure] Boolean value indicating if the cookie transmission requires a
* secure transmission
*/
function setCookie(name, value, expires, path, domain, secure) {
document.cookie= name + "=" + escape(value) +
((expires) ? "; expires=" + expires.toGMTString() : "") +
((path) ? "; path=" + path : "") +
((domain) ? "; domain=" + domain : "") +
((secure) ? "; secure" : "");
}
</script>
<script type="text/javascript">
/**
* Gets the value of the specified cookie.
*
* name Name of the desired cookie.
*
* Returns a string containing value of specified cookie,
* or null if cookie does not exist.
*/
function getCookie(name) {
var dc = document.cookie;
var prefix = name + "=";
var begin = dc.indexOf("; " + prefix);
if (begin == -1) {
begin = dc.indexOf(prefix);
if (begin != 0) return null;
} else {
begin += 2;
}
var end = document.cookie.indexOf(";", begin);
if (end == -1) {
end = dc.length;
}
return unescape(dc.substring(begin + prefix.length, end));
}
</script>
<script type="text/javascript">
/**
* Deletes the specified cookie.
*
* name name of the cookie
* [path] path of the cookie (must be same as path used to create cookie)
* [domain] domain of the cookie (must be same as domain used to create cookie)
*/
function deleteCookie(name, path, domain) {
if (getCookie(name)) {
document.cookie = name + "=" +
((path) ? "; path=" + path : "") +
((domain) ? "; domain=" + domain : "") +
"; expires=Thu, 01-Jan-70 00:00:01 GMT";
}
}
</script>
What does the JavaScript snippet do?
This snippet is a little long but very useful, it will allow your site to store information on the viewer’s computer then read it at another point in time. This snippet can be used in many different ways to accomplish different tasks.
Preload your images
Quick Sample
<script type="text/javascript">
var images = new Array();
function preloadImages(){
for (i=0; i < preloadImages.arguments.length; i++){
images[i] = new Image();
images[i].src = preloadImages.arguments[i];
}
}
preloadImages("logo.jpg", "main_bg.jpg", "body_bg.jpg", "header_bg.jpg");
</script>
What does the JavaScript snippet do?
This snippet will prevent your site from having that awkward time when it is only displaying part of the site; this not only looks bad but is also unprofessional. All you have to do is add your images to the preloadImages section and you are ready to roll.
E-mail Validation
Quick Sample
Head:
<script type="text/javascript">
function validateEmail(theForm) {
if (/^w+([.-]?w+)*@w+([.-]?w+)*(.w{2,3})+$/.test(theForm.email-id.value)){
return(true);
}
alert("Invalid e-mail address! Please enter again carefully!.");
return(false);
}
</script>Body:
<form onSubmit="return validateEmail(this);" action="">
E-mail Address:
<input type="text" name="emailid" />
<input type="submit" value="Submit" />
<input type="reset" value="Reset" />
</form>
What does the JavaScript snippet do?
This snippet will validate that a properly formatted E-mail address is entered in a form, it cannot guarantee that the E-mail address is real, there is no way to check for that with JavaScript.
No Right-Click
Quick Sample
<script type="text/javascript">
function f1() {
if(document.all) { return false; }
}
function f2(e) {
if(document.layers || (document.getElementById &! document.all)) {
if(e.which==2 || e.which==3) { return false; }
}
}
if(document.layers) {
document.captureEvents(Event.MOUSEDOWN);
document.onmousedown = f1;
}
else {
document.onmouseup = f2;
document.oncontextmenu = f1;
}
document.oncontextmenu = new function("return false");
</script>
What does the JavaScript snippet do?
This snippet will prevent the viewer from being able to right-click on your page. This can discourage the average user from borrow images or code from your site.
Display Random Quotes
Quick Sample
Head:
<script type="text/javascript">
writeRandomQuote = function () {
var quotes = new Array();
quotes[0] = "Action is the real measure of intelligence.";
quotes[1] = "Baseball has the great advantage over cricket of being sooner ended.";
quotes[2] = "Every goal, every action, every thought, every feeling one experiences, whether it be consciously or unconsciously known, is an attempt to increase one’s level of peace of mind.";
quotes[3] = "A good head and a good heart are always a formidable combination.";
var rand = Math.floor(Math.random()*quotes.length);
document.write(quotes[rand]);
}
writeRandomQuote();
</script>Body:
<script type="text/javascript">writeRandomQuote();</script>
What does the JavaScript snippet do?
Ok so this is not a snippet that all sites would use but it can be used to display more than just random quotes. You can change the content ok the quotes to whatever you want and have random images or text displayed anywhere on your site.
Previous/Next Links
Quick Sample
<a href="javascript:history.back(1)">Previous Page</a> | <a href="javascript:history.back(-1)">Next Page</a>
What does the JavaScript snippet do?
This snippet is great if you have multiple pages on an article or tutorial. It will allow the user the browse between the pages with ease. It is also small and light weight from a resource point of view.
Bookmark a Page
Quick Sample
<a href="javascript:window.external.AddFavorite(‘http://www.yoursite.com’, ‘Your Site Name’)">Add to Favorites</a>
What does the JavaScript snippet do?
This snippet will allow the user to bookmark your page with ease; all they have to do is click the link. Its little features like this that can increase your viewers overall experience.
Easy Print Page Link
Quick Sample
<a href="javascript:window.print();">Print Page</a>
What does the JavaScript snippet do?
This little link will allow your views to easily print your page. It utilizes the quick print feature already setup by your browser and utilizes no resources until it is clicked.
Show Formatted Date
Quick Sample
Head:
<script type="text/javascript">
function showDate() {
var d = new Date();
var curr_date = d.getDate();
var curr_month = d.getMonth() + 1; //months are zero based
var curr_year = d.getFullYear();
document.write(curr_date + "-" + curr_month + "-" + curr_year);
}
</script>Body:
<script type="text/javascript">showDate();</script>
What does the JavaScript snippet do?
This snippet will allow you to display the current date anywhere on your webpage and does not need to be updated. Simply put it in place and forget about it.
Comma Separator
Quick Sample
Head:
<script type="text/javascript">
function addCommas(num) {
num += ”;
var n1 = num.split(‘.’);
var n2 = n1[0];
var n3 = n1.length > 1 ? ‘.’ + n1[1] : ”;
var temp = /(d+)(d{3})/;
while (temp.test(n2)) {
n2 = n2.replace(temp, ” + ‘,’ + ”);
}
var out = return n2 + n3;
document.write(out);
}
</script>Body:
<script type="text/javascript">addCommas("4550989023");</script>
What does the JavaScript snippet do?
This snippet would be used mainly by sites that use numbers often. This snippet will keep your numbers looking the same across the board. All you have to do is copy the body line where you want to add a number and replace the number there with your number.
Get the Display Area of a Browser
Quick Sample
<script type="text/javascript">
<!–
var viewportwidth;
var viewportheight;
// the more standards compliant browsers (mozilla/netscape/opera/IE7) use window.innerWidth and window.innerHeight
if (typeof window.innerWidth != ‘undefined’)
{
viewportwidth = window.innerWidth,
viewportheight = window.innerHeight
}
// IE6 in standards compliant mode (i.e. with a valid doctype as the first line in the document)
else if (typeof document.documentElement != ‘undefined’
&& typeof document.documentElement.clientWidth !=
‘undefined’ && document.documentElement.clientWidth != 0)
{
viewportwidth = document.documentElement.clientWidth,
viewportheight = document.documentElement.clientHeight
}
// older versions of IE
else
{
viewportwidth = document.getElementsByTagName(‘body’)[0].clientWidth,
viewportheight = document.getElementsByTagName(‘body’)[0].clientHeight
}
document.write(‘<p>Your viewport width is ‘+viewportwidth+’x’+viewportheight+'</p>’);
//–>
</script>
What does the JavaScript snippet do?
This snippet will allow you to get the width and height of the display area in your views browser. This will give the designer the ability to create and use different displays based on the size of the user’s browser window.
Redirect with Optional Delay
Quick Sample
<script type="text/javascript">
setTimeout( "window.location.href =
‘http://walkerwines.com.au/’", 5*1000 );
</script>
What does the JavaScript snippet do?
This snippet will allow you to redirect your viewers to another page and it has the option of setting a delay. The use of this snippet is pretty self-explanatory and it is a very valuable tool to have in your belt.
Detect iPhones
Sample
<script type="text/javascript">
if((navigator.userAgent.match(/iPhone/i)) || (navigator.userAgent.match(/iPod/i))) {
if (document.cookie.indexOf("iphone_redirect=false") == -1) {
window.location = "http://m.espn.go.com/wireless/?iphone&i=COMR";
}
}
</script>
What does the JavaScript snippet do?
This snippet will allow you to detect if your viewer is on an iPhone or iPod allowing you to display different content to them. This snippet is invaluable with how large the mobile market is and it is only going to continue to grow.
Print Message to Status Bar
Quick Sample
<script language="javascript" type="text/javascript">
<!–
window.status = "<TYPE YOUR MESSAGE>";
// –>
</script>
What does the JavaScript snippet do?
This little snippet will allow you to print a message to the status bar. You can display recent or important news in an area the will catch the eye of the user.
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