下拉框获得自定义标签的值

<select id = "list" >
	<option tips="1">公告</option>
	<option tips="2">活动</option>
	<option tips="3">版本</option>
</select>
<input id="intro" type="text" name="type">

var oSelect = document.getElementById("list");
	var oInput = document.getElementById("intro");
	oInput.value = $("#list").find("option:selected").attr("tips");
	oSelect.onchange = function(e){
		var opt = this.options[this.options.selectedIndex];
		oInput.value = opt.getAttribute("tips");
	}

默认显示也为自定义标签的值