登录时，当用户名或密码一项为空时，如何弹出提示框提示用户，两项都添加后再进行提交操作？
一下是代码，应如何添加？
<%@ taglib uri= "/WEB-INF/struts-tiles.tld " prefix= "tiles " %>
<%@ taglib uri= "/WEB-INF/struts-nested.tld " prefix= "nested " %>
<%@ taglib uri= "/WEB-INF/struts-logic.tld " prefix= "logic " %>
<%@ taglib uri= "/WEB-INF/struts-template.tld " prefix= "template " %>
<%@ taglib uri= "/WEB-INF/struts-bean.tld " prefix= "bean " %>
<%@ taglib uri= "/WEB-INF/struts-html.tld " prefix= "html " %>
<%@ page contentType= "text/html; charset=GBK " %>
<html:html xhtml= "true " locale= "true ">
<head>
<title>
login.jsp
</title>
<html:base/>
</head>
<body>
<h1> h1>
<p>
<html:form action= "/loginAction.do " method= "POST ">
<html:text property= "username "/>
<br>
<html:password property= "password "/>
<br>
<html:submit property= "submit " value= "Submit "/> <br>
<html:reset value = "Reset "/>
</html:form>
</body>
</html:html>
[解决办法]
<%@ taglib uri= "/WEB-INF/struts-tiles.tld " prefix= "tiles " %>
<%@ taglib uri= "/WEB-INF/struts-nested.tld " prefix= "nested " %>
<%@ taglib uri= "/WEB-INF/struts-logic.tld " prefix= "logic " %>
<%@ taglib uri= "/WEB-INF/struts-template.tld " prefix= "template " %>
<%@ taglib uri= "/WEB-INF/struts-bean.tld " prefix= "bean " %>
<%@ taglib uri= "/WEB-INF/struts-html.tld " prefix= "html " %>
<%@ page contentType= "text/html; charset=GBK " %>
<html:html xhtml= "true " locale= "true ">
<head>
<title>
login.jsp
</title>
<html:base/>
</head>
<body>
<script type= "text/javascript "> -------------------------------增加的
function submit1()
{
if(za.aa.value== " "){
alert( "请输入发送信息内容 ");
za.aa.focus();
return false;
}
}
</script>
<h1> </h1>
<p>
<html:form action= "/loginAction.do " name= "za " method= "POST ">
<html:text name= "aa " property= "username "/>
<br>
<html:password property= "password "/>
<br>
<html:submit property= "submit " onclick= "return submit1() " value= "Submit "/> <br> ----增加的submit1() "
<html:reset value = "Reset "/>
</html:form>
</body>
</html:html>
[解决办法]
function check() {
var usernameText = document.getElementsByName( "username ")[0];
var passwordText = document.getElementsByName( "password ")[0];
// 去掉首尾的空格
username = usernameText.value.replace(/(^\s*)|(\s*$)/g, " ");
password = passwordText.value.replace(/(^\s*)|(\s*$)/g, " ");
if(username.length==0) {
alert( "用户名不能为空！ ");
usernameText.focus();
usernameText.select();
return false;
}
if(password.length==0) {
alert( "密码不能为空！ ");
passwordText.focus();
passwordText.select();
return false;
}
return true;
}
把 form 和 username 的 name 属性去掉，不用加。它的名字就是 loginForm 和 username，你可以通过查看页面源代码可以看到的。