下拉菜单赋值test框在safari下没法赋值,麻烦高手指点

[cropcs]

问题1:js下拉菜单选择后赋值给model和digest的test文本框,在ie显示正常, 在safari下拉菜单正常显示,却没法赋值给test框.
jsp里的js代码

<script>
onload="document.getElementsByName('choice')[0].focus()"
</script>

<select name="choice" onchange="forproduct(this)">
<option value='' model='' digests=''>品名</option>
<% for ( int i=0; i<product_docs.length; i++ ){%>
<option value='<%=i%>' model='<%=digests='<%=product_docs[i].get("digest")%>' ><%=product_docs[i].get("name")%></option>
<% }
%>
</select>



<font color=green>产品型号:</font> <input type="text" name="model" size="8" maxlength="8" style='color:violet;font-weight:bold' readonly='true'>
<font color=green>产品备注:</font> <input type="text" name="digests" size="20" maxlength="20" style='color:blue' readonly='true'>



<script>
function forproduct(obj){
var selectedOption=obj.options[obj.selectedIndex];
document.getElementById("model").value = selectedOption.model;
document.getElementById("digests").value = selectedOption.digests;
}
</script>

请问如何才能让在safari里选择下拉菜单的项然后赋值给test框呢? ie一切正常; 麻烦高手指点,万分感谢