Rob Bell

Recent posts

Sleepless in south-east London: Surviving your first hackathon

About a month after joining ASOS as an engineer and full of fresh-faced naivety, I willingly signed up to join a team taking part in the RetailWeek TechSprint – a 24-hour hackathon aimed at creating innovation for online retail. Armed with my laptop, a toothbrush and a loose grasp of the latest front-end frameworks, I set off for the InterContinental hotel at the O2 for a day and night of programming, pitching and perseverance. These are the things I learnt.

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A beginner's guide to Big O notation

Big O notation is used in Computer Science to describe the performance or complexity of an algorithm. Big O specifically describes the worst-case scenario, and can be used to describe the execution time required or the space used (e.g. in memory or on disk) by an algorithm.

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Server-side ValidationGroup switching

Often when validating a page in ASP.NET there’s the need to switch between ValidationGroups. A good example is a shopping cart where the user can choose to have products delivered to the account address or enter an alternative address, all within one page submission. If the user chooses to use an alternative address we need to validate that the required fields for the new address have been completed; if they decide to use their existing address then we need to validate that instead.

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Bookmarks is a quick and simple web bookmarking application developed in PHP. Bookmarks are organised by tags, and there is a simple search facility which searches on both tags and bookmark titles.

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Handling clicks outside a specified area in jQuery

Recently I've needed to handle clicks in jQuery which occur anywhere inside a page but outside a specified area. I've been working on a drop down list control which contains a list of checkboxes. The list of checkboxes is shown and hidden by clicking the preceding h4 title, mimicing the functionality of an ordinary drop down list. I wanted to extend this functionality to hide the list when the user clicked anywhere outside the containing div.

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