EasyUI：form表单提交前验证

使用onSubmit进行验证，如果发挥false可以终止提交

$('#newRoleUser-form').form('submit', {
    url: '/admin/createRoleUser',
    onSubmit: function () {
        let personID = $('#personid').val();
        let flag;
        $.ajax({
            url: '/search/PersonIdExistOrNot',
            type: 'POST',
            data: { personId: personID },
            async: false,
            success: function (data) {
                flag = data;
            }
        });
        if (flag === "false") {
            $.messager.alert('信息提示', '该账户已配置角色！');
            return false;
        } 
    },
    success: function (data) {
        var resp = JSON.parse(data);
        if (resp.status == "success") {
            $.messager.alert('信息提示', '提交成功！');
            $('#newRoleUser').dialog('close');
            reload();
        }
        else {
            $.messager.alert('信息提示', '提交失败！', resp.msg);
        }
    }
});