删除成功或失败提示：
boolean boo=new BookManageBiz().delete(bm);
String info=boo?"删除成功":"删除失败";
String str="<script type='text/javascript'>alert('"+info+"');window.location.href="+req.getContextPath()+"/findall.do';</script>";
PrintWriter out=resp.getWriter();
out.print(str);
out.flush();
out.close();
删除询问：
<a href="javascript:mydelete(${b.b_Id})">删除</a>
<script type="text/javascript">
function mydelete(id){
if(confirm("你确定要删除吗?")){
window.location.href="/20170519/delete.do?id="+id;
}
}
</script>
输入框验证：
<script type="text/javascript">
window.onload = function() {
document.getElementById("myForm").onsubmit = function() {
var arr=["b_name","b_author","b_time"];
var a=["图书名称不能为空","作者姓名不能为空","购买日期不能为空"];
for(var i=0;i<arr.length;i++){
if(myId(arr[i]).length==0){
alert(a[i]);
return false;
}
}
if(myId("b_time").length>0){
var reg=/\d{4}-([1-12]|\d{2})-([1-9]|\d{2})/;
if(!reg.test(myId("b_time"))){
alert("日期格式错误，必须为yyyy-MM-dd");
return false;
}
}
return true;
}
function myId(id){
return document.getElementById(id).value;
}
}
</script>
