Select What's True Regarding All-in-one Computers

I have a table containing a unique ID field. Another field (REF) contains a reference to another dataset's ID field. Now I have to select all datasets where REF points to a dataset that doesn't exi...

Select What's True Regarding All-in-one Computers 1

If I just need 2/3 columns and I query SELECT * instead of providing those columns in select query, is there any performance degradation regarding more/less I/O or memory? The network overhead mig...

Add an attribute data-selected to each element?

Now, doSomething() only gets triggered when the selection changes. I want to trigger doSomething() when the user selects any option, possibly the same one again. I have tried using an "onClick" handler, but that gets triggered before the user starts the selection process. So, is there a way to trigger a function on every select by the user? Update: The answer suggested by Darryl seemed to work ...