點擊按鈕設置ifram表單隱藏顯示

<div id="div_1" οnclick="myfunction()">
<span class="label label-default radius" type="button" value="隱藏" οnclick="myfunction()" style="background-color:#C5D9E8;"  >&nbsp;</span>
</div>
 <iframe id="reset_b"  name="his_d" src="" width=100% height=46% scrolling="auto" frameborder="0"></iframe>
 
<script>
  function myfunction(){
  if(document.getElementById('reset_b').style.visibility=='hidden'){
  document.getElementById('reset_b').style.visibility='visible';
  document.getElementById('reset_b').style.height="50%"
  document.getElementById('reset_a').style.height="50%"
 
 
  }else{
  document.getElementById('reset_b').style.visibility='hidden';
  document.getElementById('reset_b').style.height="0"
  document.getElementById('reset_a').style.height="95%"
 
  }
  }
 
 
 
</script>