asp.net中弹框提示的几种写法

1、新建一个VS开发项目，新建ASP.net窗体

2、在前台JS中：function check(){if( document.getElementById("用户输入框ID").value==""){alert("用户名不能为空");}}在后台提示：Response.Write("<script>alert('操作错误');</script>");或RegisterStartupScript("", "<script>alert('操作错误')</script>");或RegisterClientScriptBlock("","<script>alert('用户名错误');</script>");

3、在前台JS中：function check(){if( document.getElementById("用户输入框ID").value==""){alert("用户名不能为空");}}在后台提示：Response.Write("<script>alert('操作错误');</script>");或RegisterStartupScript("", "<script>alert('操作错误')</script>");或RegisterClientScriptBlock("","<script>alert('用户名错误');</script>");