<div class="check">
 <input id="checkbox1" class="checkbox" type="checkbox" checked ="checked" /><label>记住密码</label>
 </div>

.check{
  text-align: right;
  font-size:24px;
  height: 50px; 
  width: 150px;
  background: url(img/btn_1.png) left center no-repeat;
  }
.checkbox{
  width:50px;
  height: 50px;
  vertical-align: middle;
  filter:alpha(opacity=0); 
  -moz-opacity:0; 
  -khtml-opacity: 0; 
  opacity: 0; 
  }
label {
  vertical-align: middle;
  }

toggle(objs) {
  $(objs).each(function(){
   if ($(this).is(':hidden')) $(this).show(); else $(this).hide();
  });
 }

$(document).ready(function(){
 var flag = 1;
 $(".check").click(function(){
  if(flag == 1){
   $(".check").css("background","url(img/btn_1.png) left center no-repeat");
   flag = 0;
  } else{
   $(".check").css("background","url(img/btn_2.png) left center no-repeat");
   flag = 1;
  }
 })
});