怎么循环取得页面上所有select下拉框的value

Question

var objs=document.getElementsByTagName("select")
for(var i=0;i<objs.length;i++)
{
   alert(objs[i].value)
}

Answer 1

<script>
function fnSel()
{
var txt="";
var obj = document.getElementById('form1');
for(var i=1;i<obj.length;i++)
if(obj.elements[i].tagName == 'SELECT')
for(var j=0;j<obj.elements[i].options.length;j++)
txt += obj.elements[i].options[j].value+",";
alert(txt);
}
</script>
---------------------------------
<form id="form1">
<SELECT id="s1">
<OPTION VALUE="11" SELECTED>11</OPTION>
<OPTION VALUE="22">22</OPTION>
</SELECT>
<SELECT id="s2">
<OPTION VALUE="aa" SELECTED>aa</OPTION>
<OPTION VALUE="bb">bb</OPTION>
</SELECT>
<input type="button" id="btn" value="button" onclick="fnSel()"/>
</form>