未捕获的类型错误：$ 不是函数
<script type="text/javascript">
layui.use(['layer'], function(){
$ = layui.juqery;
layer = layui.layer;
});
function dologin(){
var username = $('#username').val();
var pwd = $('#pwd').val();
var verifycode = $('#verifycode').val();
if (username == '') {
layer.alert('请输入用户名',{icon:2});
return;
}
if (pwd == '') {
layer.alert('请输入密码',{icon:2});
return;
}
if (verifycode == '') {
layer.alert('请输入验证码',{icon:2});
return;
}
}
</script>
报错：Uncaught TypeError: $ is not a function
