how to generate circle using javascript

Question

How can i create a Circle in Html using javascript. Does it can be done using Javascript or not? I have done creating rectangles and squares but don't know how to accomplish a circle.

Solution 1

You need to use the following liabrary:-

Put the code in your head tag.

<script type="text/JavaScript" src="jsDraw2D.js"></script>

It is available to download from here

Copy and paste the following code where you want your circle to appear...

<script type="text/JavaScript">

//Create jsGraphics object
var gr = new jsGraphics(document.getElementById("canvas"));

//Create jsColor object
var col = new jsColor("red");

//Create jsPen object
var pen = new jsPen(col,1);

//Draw a Line between 2 points
var pt1 = new jsPoint(20,30);
var pt2 = new jsPoint(120,230);
gr.drawLine(pen,pt1,pt2);

//Draw filled circle with pt1 as center point and radius 30. 
gr.fillCircle(col,pt1,30);

//You can also code with inline object instantiation like below
gr.drawLine(pen,new jsPoint(40,10),new jsPoint(70,150)); 

</script>

You can check the documentation for this from here

Solution 2

Here's a simple way to do a circle for modern browsers:

<div style='border: 3px solid red; border-radius: 50px; width: 100px; height: 100px;'>
</div>

Demo.

edit — It works better with the "box-sizing" ("-moz-box-sizing" for Firefox) set to "border-box".

<style>
  div.circle {
    border: 3px solid red;
    border-radius: 50%;
    width: 100px; height: 100px;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
  }
</style>

<div class=circle>
</div>

Solution 3

Using HTML5 Canvas and AJAX, you can do the following:

window.onload = function(){
    var canvas = document.getElementById("myCanvas");
    var context = canvas.getContext("2d");
    var centerX = canvas.width / 2;
    var centerY = canvas.height / 2;
    var radius = 10;

    context.beginPath();
    context.arc(centerX, centerY, radius, 0, 2 * Math.PI, false);
    context.fillStyle = "black";
    context.fill();
    context.lineWidth = 1;
    context.strokeStyle = "black";
    context.stroke();

};

the big line being the:

context.arc(centerX, centerY, radius, 0, 2 * Math.PI, false);

For more go see: HTML5 Canvas Tutorials

Solution 4

You can use some javascript library for the same. Like here is a third party js library which may serve your purpose

http://processingjs.org/

View more solutions

Comments

[JamesUsedHarden]

This draws a circle, but what does it have to do with AJAX?

[Bob]

there is no AJAX here (and none needed)

[thatOneGuy]

I don't see the point in downloading extra libraries when this can be done easily in css as shown below or just as easy using canvas

[thatOneGuy]

@MahdiJazini and what suggestion is that ?