Can't execute javascript on websites - timeout - only if I connect per wifi

I would like to ask you for a help.
I have a laptop and since a longer time I have the openSUSE 13.2 64bit installed there, I allow the updates to install etc. and connect to the internet per wifi/wlan (Networkmanager).
Since 2 days I can’t load some webpages or do some actions on the web. I can’t acces gmx webmail page - I can login, I see the welcome frame but where the e-mails have to be is only the loading symbol and after a time the timeout warning executes. The same when I want to send a form on some websites -ie. contact form - after clicking submit the firefox or konqueror or others, only waiting for… appear there, nothi9ng happened and after a while timeout executes. I can’t send e-mails per Thunderbird either. It executes sending, writes 100% sent and then opens a windows with timeout… what I can see and use without problems is the facebook page.
I think therefore that the problem is with javascript.
I have tried to deny the javascript in firefox then to allow it again - no action.
I have checked the firewall and ipv6 is denied as well.
The strange thing is that this behaviour is only if I connect per wifi at work. When I connect with the same laptop at home, no problem with the websites occures.
Next, at work, I have tried to access the same websites per LAN per a PC (the same router as the laptop does) and there was no problem. There is only one router, one LAN connection to it (my PC) and one WLAN connection (my laptop) in this network.
So the problem with java is only per wifi connection at my laptop and only at work.
What can it be?
I have tried to remove /etc/resolv.conf but no change
many thanks

Hi, welcome

I hope you tried the removal of /etc/resolv.conf at work, connected through wifi.

Can you compare the network settings on the PC to those made on the laptop for the Wifi connection?

Which desktop environment is being used?

What happens if you make a wired connection from the laptop to the router?

BTW: java is not the same as javascript. Absolutely not.

I am sorry with java/javascript!
yes, the removal of /etc/resolv.conf at work, connected through wifi.
the PC has a Windows 7 installed
desktop env. is KDE, wired connection doesn’t work (neither the LAN-plug light up nor the router sees it) so I have tried to install the module r8101 for it
now: the wired connection for laptop doesn’t work but (I don’t know why) the wireless does work correctly now (I can access all the webpages) so I’m a bit unsure because the strange behaviour described here can come again. I will observe it…