jQuery英文数字组合验证码特效

一个比较好用并容易设置的英文数字组合验证码特效，可以自定义线条干扰线、干扰小点、字体、字体大小、字体颜色等等！

效果如下图：

<div class="layui-form-item">
	<div class="layui-input-block">
		<span class="decrib">验证码：</span>
		<input type="text" placeholder="请输入右侧显示的验证码" class="input-val">
		<canvas id="canvas" width="150px" height="43px">
		</canvas>
	</div>
</div>

<div class="layui-form-item">
	<div class="layui-input-block">
		<button class="layui-btn layui-btn-fluid" id="submit">确定</button>
	</div>
</div>

//验证码上显示线条

for (var i = 0; i <= 5; i++) { 
	context.strokeStyle = randomColor();
	context.beginPath();
	context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
	context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
	context.stroke();
}

//验证码上显示小点

for (var i = 0; i <= 50; i++) {
	context.strokeStyle = randomColor();
	context.beginPath();
	var x = Math.random() * canvas_width;
	var y = Math.random() * canvas_height;
	context.moveTo(x, y);
	context.lineTo(x + 1, y + 1);
	context.stroke();
}