求助：如何在頁面修改文本框內(nèi)容并寫出txt文件

求助各位大神：如何在頁面修改文本框內(nèi)容并寫出txt文件。我在頁面上輸入經(jīng)緯度信息后，并無用。感激不盡！
<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<style type="text/css">
    body, html,#l-map {width: 90%;height: 90%;overflow: hidden;margin:0;font-family:"微軟雅黑";}#r-result {width:100%;}
</style>
<script src="http://search.dangdang.com/Standard/Search/Extend/hosts/js/jquery.js"></script>
<script type="text/javascript" src="http://api.map.baidu.com/api?v=2.0&ak=nCRvMdrWkhF3kg0RsTdUvku6"></script>
<title>公交出行的時(shí)間和距離</title>

</head>
<body>
<div id="l-map"></div>
<div id="r-result"> <div class="form-group">

<label for="startlng">起點(diǎn)經(jīng)度：</label>
<input type="text" class="form-control" id="startlng" placeholder="起點(diǎn)經(jīng)度"  value=""/>
<label for="startlat">起點(diǎn)緯度：</label>
<input type="text" class="form-control" id="startlat" placeholder="起點(diǎn)緯度"  value=""/>
<label for="endlng">終點(diǎn)經(jīng)度：</label>
<input type="text" class="form-control" id="endlng" placeholder="終點(diǎn)經(jīng)度"  value=""/>
<label for="endlat">終點(diǎn)緯度：</label>
<input type="text" class="form-control" id="endlat" placeholder="終點(diǎn)緯度"  value=""/>
<input type=button id="query" value="查詢" onclick="Write2Text()">

</div></div>
</body>
</html>
<script type="text/javascript">

// 百度地圖API功能
var map = new BMap.Map("l-map");
map.centerAndZoom(new BMap.Point(118.799154,32.066449), 12);
map.enableScrollWheelZoom();
var ttime;
var tdistance;
var s = [];
var alldata=[];

var slng=document.getElementById("startlng").value;
var slat=document.getElementById("startlat").value;
var elng=document.getElementById("endlng").value;
var elat=document.getElementById("endlat").value;

var p1 = new BMap.Point(slng,slat);
var p2 = new BMap.Point(elng,elat);
var transit = new BMap.TransitRoute(map, {
    onSearchComplete: function (result) {
        if (transit.getStatus() == BMAP_STATUS_SUCCESS) {
            var firstPlan = result.getPlan(0);
            ttime = firstPlan.getDuration(true); 
            tdistance = firstPlan.getDistance(true);
            s = result.getPlan(0).getDescription(false);
            alldata=ttime+","+tdistance+","+s+"\r\n";

        }
    }
});
transit.search(p1, p2);

function Write2Text()
{
    var fso=new ActiveXObject("Scripting.FileSystemObject");
    var f=fso.CreateTextFile("C:\\Users\\enhui\\Desktop\\test.txt",true);
    f.write(alldata);
    f.Close();
}

</script>
</html>