Technology Questions

Canvas is an element that is used for the graphics for the web page. It uses JavaScript to bring the graphics functionality live. It allows easy way to draw the graphics and use different types of tools to create drawing on the web page. Canvas is just a rectangular area that controls the pixel of every element that is used in the web page. Canvas uses methods like paths, circles, etc. The canvas element will be used as follows:

<canvas id="can" width="200" height="100"></canvas>

The canvas element includes id, width and height settings and with the javascript it gets used like:

<script type="text/javascript">

var c=document.getElementById("can");

var ctx=c.getContext("2d");

ctx.fillStyle="#FF0000";

ctx.fillRect(0,0,150,75);

</script>

When ever two or more threads are sharing same data for updating then unpredicted result will be there in the data.

For Example take a thread is depositing amount in Account Object and another thread is withdrawing amount from the same Account Object.

when ever both threads are executed simultaneously then unexpected result is stored in the balance of the  Account Object. 

In angular.js services are the singleton objects or functions that are used for carrying out specific tasks.
It holds some business logic and these function can be called as controllers, directive, filters and so on.

GROUP BY partitions the selected rows on the distinct values of the column on which you group by. HAVING selects GROUPs which match the criteria specified

Customer Information Control System (CICS) is an online transaction processing monitor from IBM that acts as an interface between the operating system and application programs to provide rapid high-volume online transaction processing.

A network in which there are multiple network links between computers to provide multiple paths for data to travel.

I/O operations like reading or writing a file is not possible with client-side javascript. However , this can be done by coding a Java applet that reads files for the script.