Crafty.js

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/crafty/0.5.4/crafty-min.js"></script>

JavaScript

var viewportWidth = 100;
var viewportHeight = 100;
Crafty.init(viewportWidth,viewportHeight);
Crafty.canvas.init();  
Crafty.scene("game", function() 
{
    Crafty.background("#000");
    var clickText = Crafty.e("2D, DOM, Text")
        .attr({x:viewportWidth/4, y:180, w:150, h:40})
        .text("Click somewhere")
        .css({"font": "10pt Arial", "color": "#FFF", "text-align": "left"});
    //Create an entity to track the mouse clicks
    var mouseTracker = Crafty.e("2D, Mouse").attr({ w:viewportWidth, h:viewportHeight, x:0, y:0 });
    mouseTracker.bind("Click", function(e) 
    {
        //The Crafty.mousePos.x/y returns the mouse position in pixels inside the stage
        clickText.text("Clicked:"+ Crafty.mousePos.x +", "+ Crafty.mousePos.y)
    }); 
});
Crafty.scene("game");