<select name="select" onchange="changeVal(this)">
	<option value="1" data="text1_2">text1_3</option>
	<option value="2" data="text2_2">text2_3</option>
	<option value="3" data="text3_2">text3_3</option>
 </select>

function changeVal(obj){
	var index=obj.selectedIndex;
	var rela=obj.children[index];
	alert(rela.value);  //获取选中项的value值
	alert(rela.getAttributeNode("data").value);  //获取选中项的data值
	alert(rela.innerHTML);  //获取选中项的内容值
}