一个DOM问题,麻烦解决下 谢谢

Question

<form action="<%=imgpath%>/budget/zhichubudget/projecttree.do" method="post" name="model" id="XXX">
<input type="hidden" name="useArea" value="">
<table class="tabletop">
<tr>
             <td class="tabletop" align="right">
工程类型:
<select name="gongchengTypeID" id="gongchengTypeID" onchange="gcList()">
<option value="">
      全部
</option>
<option value="">
无工程
</option>
</select>
<script type="text/javascript">
var wc = document.getElementById("gongchengTypeID"), os = wc.options, i;
for (i = 0 ; i < os.length ; i ++) {
if (/全部/.test(os[i].innerHTML)) {
alert(i);
}
}
</script>

Answer 1

<script type="text/javascript">
var gcItems = document.getElementById("gongchengTypeID").getElementsByTagName("option");
alert(gcItems[0].firstChild.nodeValue);
</script>

Answer 2

<script type="text/javascript">
var gcItems = document.getElementById("gongchengTypeID");
for(var i=0;i<gcItems.options.length;i++){
    if(gcItems.options[i].text=='全部'){
        alert(i);
    }
}
</script>