Raphael - drop a box in another box

by Reusablecode

HTML

Drag and drop pink box.<br/>
Can't move it out of the black box once you enter it.
<div id="canvas"></div>

JavaScript

window.onload = function() {
var nowX, nowY, R = Raphael("canvas", 500, 500),
    c = R.rect(200, 200, 40, 40).attr({
            fill: "hsb(.8, 1, 1)",
            stroke: "none",
            opacity: .5,
            cursor: "move"
        }),
    j = R.rect(0,0,100,100),
    // start, move, and up are the drag functions
    start = function () {
        // storing original coordinates
        this.ox = this.attr("x");
        this.oy = this.attr("y");
        this.attr({opacity: 1});
        if (this.attr("y") < 60 &&  this.attr("x") < 60)
            this.attr({fill: "#000"});        
    },
    move = function (dx, dy) {
        // move will be called with dx and dy
        if (this.attr("y") > 60 || this.attr("x") > 60)
            this.attr({x: this.ox + dx, y: this.oy + dy}); 
        else {
            nowX = Math.min(60, this.ox + dx);
            nowY = Math.min(60, this.oy + dy);
            nowX = Math.max(0, nowX);
            nowY = Math.max(0, nowY);            
            this.attr({x: nowX, y: nowY });
            if (this.attr("fill") != "#000") this.attr({fill: "#000"}); 
        }
    },
    up = function () {
        // restoring state
        this.attr({opacity: .5});
        if (this.attr("y") < 60 && this.attr("x") < 60)
            this.attr({fill: "#AEAEAE"});            
    };   
    // rstart and rmove are the resize functions;
    c.drag(move, start, up);
};