What is npm? and how to install

npm is very easy for the javaScript developers to developed a reusable code and makes it easy to update the code that you’re sharing, so you can build amazing things.

npm is installed with Node.js

Click here to download

Check that you have node and npm installed

To check if you have Node.js installed, run this command in your terminal:

node -v

To check if you have npm installed :

npm -v


Implement Validation for HTML form without JavaScript Learn Regular Expression

How often have you found yourself writing some quickie regular expression to verify a particular textbox. Thanks to the new pattern attribute, we can insert a regular expression directly into our markup.

<form action=”” method=”post”>
<label for=”username”>Create a Username: </label>
<input type=”text”
placeholder=”4 <> 10″
<button type=”submit”>Go </button>

If you’re moderately familiar with regular expressions, you’ll be aware that this pattern: [A-Za-z]{4,10} accepts only upper and lowercase letters. This string must also have a minimum of four characters, and a maximum of ten.

Notice that we’re beginning to combine all of these new awesome attributes!

When CSS was Introduce

The saga of CSS starts in 1994. One of the authors of this book works at CERN – the cradle of the Web – and the Web is starting to be used as a platform for electronic publishing. One crucial part of a publishing platform is missing, however: there is no way to style documents. For example, there is no way to describe a newspaper-like layout in a Web page. Having worked on personalized newspaper presentations at the MIT Media Laboratory, Håkon saw the need for a style sheet language for the Web.

Style sheets in browsers were not an entirely new idea. The separation of document structure from the document’s layout had been a goal of HTML from its inception in 1990. Tim Berners-Lee wrote his NeXT browser/editor in such a way that he could determine the style with a simple style sheet. However, he didn’t publish the syntax for the style sheets, considering it a matter for each browser to decide how to best display pages to its users. Other browsers, including Pei Wei’s Viola (1992) and the Harmony browser (1993)The Hyper-G system was one of the Web’s early competitors for the Hyper-G system had comparable style languages.

But instead of more advanced style sheets, the browsers that followed offered their users fewer and fewer options to influence the style. In 1993, NCSA Mosaic, the browser which made the Web popular, came out. Stylewise, however, it was a backwards step as it only allowed its users to change certain colors and fonts.

Meanwhile, writers of Web pages were complaining that they didn’t have enough influence over how their pages looked. One of the first questions from an author new to the Web was how to change fonts and colors of elements. HTML at that time did not provide this functionality – and rightfully so. This excerpt from a message sent to the www-talk mailing list early in 1994, gives a sense of the tensions between authors and implementors:

Learn Simple Animation Through CSS

div {
width: 100px;
height: 100px;
background-color: red;
-webkit-animation-name: example; /* Chrome, Safari, Opera */
-webkit-animation-duration: 4s; /* Chrome, Safari, Opera */
animation-name: example;
animation-duration: 4s;

/* Chrome, Safari, Opera */
@-webkit-keyframes example {
from {background-color: red;}
to {background-color: yellow;}

/* Standard syntax */
@keyframes example {
from {background-color: red;}
to {background-color: yellow;}