module

require 'rubygems'
require 'RMagick'
class NoisyImage
  include Magick
  attr_reader :code, :code_image
  Jiggle = 15
  Wobble = 15
  def initialize(len)
    chars = ('a'..'z').to_a - ['a','e','i','o','u']
    code_array=[]
    1.upto(len) {code_array << chars[rand(chars.length)]}
    granite = Magick::ImageList.new('xc:#EDF7E7')
    canvas = Magick::ImageList.new
    canvas.new_image(32*len, 50, Magick::TextureFill.new(granite))
    text = Magick::Draw.new
    text.font_family = 'times'
    text.pointsize = 40
    cur = 10

    code_array.each{|c|
      rand(10) > 5 ? rot=rand(Wobble):rot= -rand(Wobble)
      rand(10) > 5 ? weight = NormalWeight : weight = BoldWeight
      text.annotate(canvas,0,0,cur,30+rand(Jiggle),c){
        self.rotation=rot
        self.font_weight = weight
        self.fill = 'green'
      }
      cur += 30
    }
    @code = code_array.to_s
    @code_image = canvas.to_blob{
      self.format="JPG"
    }
  end
end

controller

class CodeController < ActionController::Base
  def code_image
    @noisy = NoisyImage.new(4) #生成一个有4字符的图片
    @code=""
    @code.insert(0, @noisy.code[2])
    @code.insert(1, @noisy.code[7])
    @code.insert(2, @noisy.code[12])
    @code.insert(3, @noisy.code[17])
    session[:code] = @code
    send_data @noisy.code_image, :type => 'image/jpeg', :disposition => 'inline'
  end
end

view

<img src="/code/code_image" id="code_img"  onclick="code_refresh()" />
...
<script>
function code_refresh(){
    $("#code_img").attr("src","/code/code_image");
}
</script>

点击验证码之后，不刷新 修改 js 代码

$("#code_img").attr("src","")

img 标签改变为

但是页面中验证码依然存在 请问该如何实现点击验证码进行刷新？