How do I draw in arrow on a web browser

Question

Given two point, (x, y) and (x1, y1), how do I draw an arrow between these point a the web browser. Can jQuery or HTML5 does this?

Answer 1

You'll also need a little high school trigonometry to draw the arrowhead.

var arrowHeadLength = 10; //whatever arbitrary value you want
// Line angle
var lineAngle = Math.atan ( (Y2-Y1)/(X2-X1) )
// Angle for arrow heads
var end1 = lineAngle + 45 * Math.PI/180
var end2 = lineAngle - 45 * Math.PI/180
// end points of arrow heads
var y3 = y2 - arrowHeadLength * Math.sin(end1)
var x3 = x2 - arrowHeadLength * Math.cos(end1)
var y4 = y2 - arrowHeadLength * Math.sin(end2)
var x4 = x2 - arrowHeadLength * Math.cos(end2)