Access Java / Servlet / JSP / JSTL / EL variables in JavaScript -


i have form in jsp. have populate based on request object (from servlet). how use java script accessing request object attributes or if can suggest me other better way populate form dynamically?

you need realize java/jsp merely html/css/js code producer. need let jsp print java variable if javascript variable , generated html/js code output syntactically valid.

provided java variable available in el scope ${foo}, here several examples how print it:

<script>var foo = '${foo}';</script> 
<script>somefunction('${foo}');</script> 
<div onclick="somefunction('${foo}')">...</div>

imagine java variable has value "bar", jsp generate html can verify rightclick, view source in webbrowser:

<script>var foo = 'bar';</script> 
<script>somefunction('bar');</script> 
<div onclick="somefunction('bar')">...</div>

do note singlequotes mandatory in order represent string typed variable in js. if have used var foo = ${foo}; instead, print var foo = bar;, may end in "bar undefined" errors in when attempt access further down in js code (you can see js errors in js console of browser's web developer toolset can open pressing f12 in chrome/firefox23+/ie9+). note if variable represents number or boolean, doesn't need quoted, work fine.

if variable happens originate user-controlled input, keep in mind take account xss attack holes , js escaping. near bottom of our el wiki page can find example how create custom el function escapes java variable safe usage in js.

if variable bit more complex, e.g. java bean, or list thereof, or map, can use 1 of many available json libraries convert java object json string. here's example assuming gson.

string someobjectasjson = new gson().tojson(someobject);

note way don't need print quoted string anymore.

<script>var foo = ${someobjectasjson};</script>

see also:


Comments

Post a Comment

Popular posts from this blog

android - InAppBilling registering BroadcastReceiver in AndroidManifest -

i'm implementing inapp billing in android app. works well, however, i'm trying decouple broadcast receiver activity manifest. suggestion in android's trivialdrive sample: // important: dynamically register broadcast messages updated purchases. // register receiver here instead of <receiver> in manifest // because call getpurchases() @ startup, therefore can ignore // broadcasts sent while app isn't running. // note: registering listener in activity bad idea, done here // because sample. regardless, receiver must registered after // iabhelper setup, before first call getpurchases(). currently there's class extends broadcastreceiver : public class iabbroadcastreceiver extends broadcastreceiver { /** * intent action receiver should filter for. */ public static final string action = "com.android.vending.billing.purchases_updated"; private final iabbroadcastlistener mlistener; public iabbroadcastreceiver(iabbroadcastlistener listener) { m...
Read more

python Tkinter Capturing keyboard events save as one single string -

is possible store keyboard events 1 string? code below stores 1 char , prints it. card reader or bar code reader, contains collection of character/ string not 1 character @ time. goal save char pressed text variable. from tkinter import * root = tk() def key(event): text= event.char text+= event.char print ("pressed", text) def callback(event): frame.focus_set() print ("clicked at", event.x, event.y) frame = frame(root, width=100, height=100) frame.bind("<key>", key) frame.bind("<button-1>", callback) frame.pack() root.mainloop() currently, creating text variable , everytime key() function gets called, , text stores last character typed. you can define text module level variable , , use module level text inside key function - text = '' def key(event): global text text+= event.char print("pressed", text)
Read more

sql server - Why does Linq-to-SQL add unnecessary COUNT()? -

here tables: create table customer ( cid int primary key, name varchar(32) ) create table ord ( oid int primary key, cid int foreign key references customer, address varchar(20) ) here's linq-to-sql statement: var aaa = c in db.customer select new { c, o = c.ord.tolist() }; and here's inexplicable query generated linq-to-sql: select [t0].[cid] [cid], [t0].[name] [name], [t1].[oid] [oid], [t1].[cid] [cid2], [t1].[address] [address], (select count(*) [dbo].[ord] [t2] [t2].[cid] = [t0].[cid]) [value] [dbo].[customer] [t0] left outer join [dbo].[ord] [t1] on [t1].[cid] = [t0].[cid] order [t0].[cid], [t1].[oid] i want understand how rid of count(*) part. it's entirely uncalled for! linq needs count(*) in order determine number of entries returned o = c.ord.tolist() .
Read more