今天在学习JS的过程中遇到了两个问题：
第一：在eclipse的内置浏览器中alert窗口跳不出来，无显示，而在外置浏览器中就可以正常显示，结果其原因是：eclipse的内置浏览器不支持trim()，把trim删掉即可。
有trim的代码：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>菜鸟教程</title>
</head>
<head>
<script>
function setCookie(cname,cvalue,exdays){
var d = new Date();
d.setTime(d.getTime()+(exdays*24*60*60*1000));
var expires = "expires="+d.toGMTString();
document.cookie = cname+"="+cvalue+"; "+expires;
}
function getCookie(cname){
var name = cname + "=";
var ca = document.cookie.split(';');
for(var i=0; i<ca.length; i++) {
// alert("*"+ca[i]+"*");
// ca[i] = "test";
var c = ca[i].trim();
// alert("*"+c+"*");
// var c = ca[i];
if (c.indexOf(name)==0) return c.substring(name.length,c.length);
}
return "";
}
function checkCookie(){
var user=getCookie("username");
if (user!=""){
alert("Welcome again " + user);
}
else {
user = prompt("Please enter your name:","");
if (user!="" && user!=null){
setCookie("username",user,30);
}
}
}
</script>
</head>
<body onload="checkCookie()"></body>
</html>
无trim的代码：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>菜鸟教程</title>
</head>
<head>
<script>
function setCookie(cname,cvalue,exdays){
var d = new Date();
d.setTime(d.getTime()+(exdays*24*60*60*1000));
var expires = "expires="+d.toGMTString();
document.cookie = cname+"="+cvalue+"; "+expires;
}
function getCookie(cname){
var name = cname + "=";
var ca = document.cookie.split(';');
for(var i=0; i<ca.length; i++) {
// alert("*"+ca[i]+"*");
// ca[i] = "test";
// var c = ca[i].trim();
// alert("*"+c+"*");
var c = ca[i];
if (c.indexOf(name)==0) return c.substring(name.length,c.length);
}
return "";
}
function checkCookie(){
var user=getCookie("username");
if (user!=""){
alert("Welcome again " + user);
}
else {
user = prompt("Please enter your name:","");
if (user!="" && user!=null){
setCookie("username",user,30);
}
}
}
</script>
</head>
<body onload="checkCookie()"></body>
</html>
第二个问题：显示多个窗口，结果在外置的浏览器中总是显示一个窗口，结果原因是：另一个窗口被屏蔽，解决办法：在浏览器的设置里找到窗口弹出设置，更改为接受所有窗口，即可。
代码如下：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script>
function open_win() {
myWindow=window.open("http://www.w3schools.com/","first");
window.open("http://www.microsoft.com/","second");
}
</script>
</head>
<body>
<form>
<input type="button" value="打开窗口" onclick="open_win()">
</form>
</body>
</html>
第三点：在JSP中测试用alert测试非常好，就跟在C里用printf测试一样！一定要记住alert经常用来测试的功能。