Answer Posted / rajiv_cogzidel

echo() doesn't return anything. But print() return true or
false.
You can give output for print() using echo(). You can notice
here print having true. So it give output 1.
Because print is a function. So it return true or false. But
echo is an statement. So it will not.
Ex:-
echo(print(d));
Output:-
d1

But you can't do this using print like this

Ex:-
print(echo(d));

Output:-
Parse error: syntax error, unexpected T_ECHO in
E:\xampp\htdocs\rajiv\valid.php on line 119


And other thing is echo() allow multiple strings using
separated by comma(,).
Here are examples

using echo()
ex:-
echo "Rajiv","\n","K.C","\n","\nHello World!","\nAgain Hello
World!";

output:-
Rajiv K.C Hello World! Again Hello World!

using print()
ex:-
print "Rajiv","\n","K.C","\n","\nHello World!","\nAgain
Hello World!";

output:-
Parse error: syntax error, unexpected ',' in
E:\xampp\htdocs\rajiv\valid.php on line 130

Some one says we cannot use double quotes in single quote.
But it's not true. It will work. Here are examples

print 'print"hai"hoo';
echo 'echo"hai"hoo';

These two give output.

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4 down vote favorite share [g+] share [fb] share [tw] I am developing my site using server side sessions using redis as backend for saving the session. Now the issue which is bothering me is of user leaving the website without logging out. I mean user simply closes the browser which causes the cookie to be deleted. Now session of that user still exists on the server and will not be used again as new login requires creating a new session due to security reasons. To avoid the case where hacker steals the old cookie and use it after user login again with same old session id. In essence user leaves the website without explicitly logging out and his session will be deleted after certain time limit of inaccessibility. I am thinking time limit of 30-60 minutes. Also with every new request from user his cookie will also be updated to keep track of when the user last time accessed the site. But nowadays, people let site remain open for long time without accessing it. For example users open facebook and gmail in new tabs and forget about them for 2-3 hours and still they are not asked to login again. Is letting a 2-3 hours old cooke access the session secure? My concern is someone steals user cookie and use it 2-3 hours later. Thinking on this topic has also forced me to question how facebook manages security if user can use a session where they are not accessing it for long periods of time and still they remain logged in. Or is it not secure for me to keep logged in when am not accessing the site session for longer period of time? It can be the case also there is some pinging mechanism using which sites keep track of user having their site open in a browser and when browser closes they are notified and can work accordingly. My website is a social network and needs all those security and usage features which a social network may need. I am new to web security and web development in general and may be the case where my above questions may seem a little basic. If you feel that is the case kindly point to some good reference where I can read and find answers to my question.

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