function chk(){
if(document.getElementById("username").value==""){
alert("用户名没有填写!");
document.getElementById("username").focus();
return false;
}
if(document.getElementById("password").value==""){
alert("密码没有填写!");
document.getElementById("password").focus();
return false;
}
}
document.writeln("");

  
document.writeln("<div class=liheight>");
document.writeln("<form name=frmlogin action='../tieba/'  method=post  >");
document.writeln("用户名：<input name=username id=username type=text class=input onkeyup='frmlogin.k.value=this.value;' /> ");
document.writeln("&nbsp;	密码：<input name=password type=password id=password class=input /> ");
document.writeln("<input name=k type=hidden value='' /> ");
document.writeln("&nbsp;<input name=lg type=image src=../images/loginbtn.gif id=lg value=登录 />");
document.writeln("&nbsp;&nbsp;<a href=../tieba/>注册</a>");
document.writeln("</form>");
document.writeln("</div>");