注销登录功能，就是返回到登录界面，一直闪退

var curr = plus.webview.currentWebview();//获取当前webview窗口
var wvs = plus.webview.all();//获取所有webview窗口
for(var i=0,len=wvs.length;i<len;i++){
console.log(">>>"+i+">>>"+len);
console.log(wvs[i].getURL()+">>>>"+curr.getURL());
if (wvs[i].getURL()==curr.getURL()) {
console.log("curr1");
plus.webview.open('login.html');//打开登录窗口
curr.close();//关闭当前窗口
console.log("curr2");
}else{
console.log("wvs1");
plus.webview.close(wvs[i]);//关闭前面窗口
console.log("wvs2");
}

                        }  

这是打印出来的信息：当i==2时就变NULL，然后就闪退出去了。应该要怎样做这个注销登录呢？？？
>>>0>>>7 at setting.html:109
file:///storage/emulated/0/Android/data/io.dcloud.HBuilder/.HBuilder/apps/HBuilder/www/login.html>>>>file:///storage/emulated/0/Android/data/io.dcloud.HBuilder/.HBuilder/apps/HBuilder/www/setting.html at setting.html:110
wvs1 at setting.html:117
wvs2 at setting.html:119
>>>1>>>7 at setting.html:109
file:///storage/emulated/0/Android/data/io.dcloud.HBuilder/.HBuilder/apps/HBuilder/www/index.html>>>>file:///storage/emulated/0/Android/data/io.dcloud.HBuilder/.HBuilder/apps/HBuilder/www/setting.html at setting.html:110
wvs1 at setting.html:117
wvs2 at setting.html:119
>>>2>>>7 at setting.html:109
null>>>>null at setting.html:110
curr1 at setting.html:112
curr2 at setting.html:115
>>>3>>>7 at setting.html:109
登录开始 at login.html:123