<form id="form" method="post">
  <input type="text" value=" " name="originalprice" />
  
  <input type="checkbox" value="news" name="box[]" />
  <input type="checkbox" value="music" name="box[]" />
  <input type="checkbox" value="read" name="box[]" />
  <input type="checkbox" value="global" name="box[]" />
</form>
<script type="text/javascript">
var obj = document.getElementsByName('box[]');
for (var i = 0; i < obj.length; i ++) obj[i].onclick = function() {
    var ar = [];
    for (var j = 0; j < obj.length; j ++) if (obj[j].checked) ar.push(obj[j].value);
    document.getElementsByName('originalprice')[0].value = ar.join('/');
}
</script>

------解决方案--------------------

HTML code
<form id="form" method="post">
<input type="text" value=" " name="originalprice" id='ipt'/><!--输入框-->
<input type="checkbox" value="news" name="box[]" onclick='setValue(this)' />
<input type="checkbox" value="music" name="box[]"  onclick='setValue(this)'/>
<input type="checkbox" value="read" name="box[]"  onclick='setValue(this)'/>
<input type="checkbox" value="global" name="box[]"  onclick='setValue(this)'/>
</form>
<script type='text/javascript'>
var result = {};
function setValue(el)
{
    var array = [];
    if(el.checked) result[el.value] = el.value;
    else delete result[el.value];
    for(var key in result) array.push(key)
    document.getElementById('ipt').value = array.join('/')
}
</script>