input.html
<!DOCTYPE html> <html> <head> <title>input.html</title> </head> <body> This is my HTML page. <br> <FORM METHOD = "Post" action = "INPUT.jsp"> 输入信息：<input type = "text" name = "info"> <input type = "submit" value ="info"> </FORM> </body> </html>
input.jsp
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>My JSP 'INPUT.jsp' starting page</title> </head> <body> This is my JSP page. <br> <% String str = request.getParameter("info"); out.println("<H1>"+str+"</H1>"); %> </body> </html>
input.html 改进，增加js 正则表达式
<script language="javascript"> function validate(f){ if(!(/w+/.test(f.info.value))){//正则表达式 alert("输入的内容不能为空！"); f.info.focus(); return false; } return true; } </script> This is my HTML page. <br> <FORM METHOD = "Post" action = "INPUT.jsp" onSubmit="return validate(this)"> 输入信息：<input type = "text" name = "info"> <input type = "submit" value ="info"> </FORM>