Javascript and Google Web Toolkit

Written by Larry Gray on . Posted in Google Web Toolkit

Javascript and Google Web Toolkit

Google web toolkit is a set of tools which allows the Java programmer to write an interface using Java swing api. Google web toolkit then converts this Swing app to Javascript so that it can be run on a webpage.

Javascript and Ajax

Written by Larry Gray on . Posted in Ajax

Javascript and Ajax

Ajax stands for Asynchronous Javascript and XML. I don't have a lot to say about Ajax at this time except to say that it has been a very important server enhancement which makes communications between the web client and web server more efficient. Ajax is a hack on the server that allows the server to send the web client a piece of a web page instead of resending the entire web page. This piece is easily handled by Javascript and the DOM (Document Object Model). The DOM of course is the web page stored in a tree model in ram. Javascript may easily manipulate this DOM model on the client side and for example update only the portion that is displaying data from a database table. I feel that Javascript and Ajax go well with Java technology. I think there is a book that I have to get titled "Java on Ajax".

However as of Java 7 and Apache Tomcat 7 the web sockets standard has been implement. Therefor I will not be learning Ajax for now or at least I see no reason. Javascript can be used with data sent via web sockets to update the DOM as easily as with Ajax as far as I know. See under the Java Menu and Web Apps Sub Menu, Java Web Sockets menu item for more info. Apache Wicket at wicket.apache.org is an api that allows you to use Ajax with Tomcat or possibly other servers.

Javascript

Written by Larry Gray on . Posted in About Javascript, Javascript

Javascript was in the beginning called Live Script. Its name was changed to Javascript or Microsoft JScript as a marketing ploy. Javascript is based on the EMCA script standard and specifications. Basically Microsoft and Netscape invented Javascript. Javascript is similar in syntax to C or Java. Many Java concepts and standards are also part of Javascript. However Javascript is not Java.

Inline Javascript example.

<html>
    <head>
        <title>JavaScript Hello World</title>
        <script>
            alert('Hello, World!);
        </script>
    </head>
    <body>
         Main body text goes here.
    </body>
</html>
Now some years back there was this concept of DHTML. DHTML was merely a combination of HTML, CSS, and Javascript along with the HTML DOM. HTML DOM is where the browsers begin to keep or store the HTML in a DOM, a DOM is a document object model. Javascript has access to this DOM. This makes it very easy for Javascript to change the currently displayed web page on the fly based on programming logic. While Javascript is by no means a substitution for Java, I feel that it is a very good complimentary tech to go with Java web development. This is why I have decided to use Javascript and support it on my web site and not because it has the Java TM name in its Name.

JQuery example.

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
    $("#hide").click(function(){
        $("p").hide();
    });
    $("#show").click(function(){
        $("p").show();
    });
});
</script>
Javascript can be run on the server side, using 'node.js', as well as on the client side(in the browser). Well known Javascript concepts are Ajax (short for Asynchronous Javascript and XML) and JQuery. I explain Ajax in an article about Ajax. JQuery is a 3rd party API that simplifies Javascript coding with HTML DOM navigation. Interesting things can be accomplished efficiently with Server Side Javascript, Ajax, JQuery and databases. Latest versions of Javascript however will obsolete JQuery with JQuery type API built in.