从图片文件中取出 JS 代码

将 JS 代码放入图片文件

void function(){
	var source = 'js.png'; // 存放JS代码的图片
	var img = document.createElement('img');
	img.src = source;
	img.onload = function(){
		var canvas = document.createElement('canvas');
		canvas.width = img.width;
		canvas.height = img.height;
		var context = canvas.getContext("2d");
		context.drawImage(img, 0, 0);
		var imageData = context.getImageData(0, 0, canvas.width, canvas.height),
		pixels = imageData.data;

		var buffer = [];
		for (var i = 0, l = pixels.length; i < l; i++) {
			if (i % 4 == 3) continue; // 第4个是透明度，不能存值（这一位的值最大是100、ASCII码会超过100）
			if (!pixels[i]) break;
			buffer.push(String.fromCharCode(pixels[i]));
		}
		document.write('<pre>'+buffer.join('')+'</pre>');
		img = null;
	}
}();