Feeds

T-Mobile JavaScript comment stripper breaks websites

It's not optimisation, it's pessimisation

Build a business case: developing custom apps

Attempts by T-Mobile to speed up mobile data connections are breaking websites.

The bug intermittently affects mobile device users and PC users using tethered connections. It is caused by "optimisations" to the sites' Javascript code made on the fly, in attempt to optimise the amount of data received. Instead of stripping out comments, the optimisation – or more precisely, "pessimisation" – also strips out strings in the code itself.

MySociety first publicised the issue last week.

A developer told us the bug struck while his team was giving a demo to a potential investor. The team subsequently spent two days tracking down what had caused the issue.

"T-Mobile have managed to strip out bits of JavaScript code as well as comments. The jQuery library suffers, too. Worse than that, the script files are cached and won't get replaced when the user moves off 3G and back on to a decent ISP: in effect, T-Mobile has broken websites permanently," said the dev.

MySociety's Matthew Somerville blamed clumsy coding:

"The T-Mobile JavaScript comment-stripper appears to be searching for '/*' and '*/' and removing everything in between. This might work in most cases; however in the jQuery library, we find a string containing '*/*', and later down the file, another string containing '*/*'. T-Mobile removes everything between the things it thinks are comment markers, even though they're actually contained within strings, causing the jQuery library to be invalid JavaScript and stopping anything using jQuery from running," he wrote.

The apparent indeterministic nature of the bug – which attacks only occasionally – has made it harder to track down. "We are investigating the issue you have raised and are taking it very seriously," T-Mobile told us. ®

Boost IT visibility and business value

More from The Register

next story
The Return of BSOD: Does ANYONE trust Microsoft patches?
Sysadmins, you're either fighting fires or seen as incompetents now
Microsoft refuses to nip 'Windows 9' unzip lip slip
Look at the shiny Windows 8.1, why can't you people talk about 8.1, sobs an exec somewhere
Munich considers dumping Linux for ... GULP ... Windows!
Give a penguinista a hug, the Outlook's not good for open source's poster child
Intel's Raspberry Pi rival Galileo can now run Windows
Behold the Internet of Things. Wintel Things
Linux Foundation says many Linux admins and engineers are certifiable
Floats exam program to help IT employers lock up talent
Microsoft cries UNINSTALL in the wake of Blue Screens of Death™
Cache crash causes contained choloric calamity
Eat up Martha! Microsoft slings handwriting recog into OneNote on Android
Freehand input on non-Windows kit for the first time
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
7 Elements of Radically Simple OS Migration
Avoid the typical headaches of OS migration during your next project by learning about 7 elements of radically simple OS migration.
BYOD's dark side: Data protection
An endpoint data protection solution that adds value to the user and the organization so it can protect itself from data loss as well as leverage corporate data.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?