Join David Powers for an in-depth discussion in this video Controlling the frequency and volume, part of Code Clinic: PHP.
- We've used the Web Audio API to generate a single tone…at full volume when the mouse button is held down…and the tone stops when the mouse button is released.…To control the frequency and volume,…we need to update the script in…tone_generator.js and create a handler…for the mousemove event.…We need to listen for the event…only when the tone is being generated.…So I'm going to add this event listener…to the startTone function.…So at the end of startTone we will add the event listener.…
So, document.addEventListener…and we're listening for mousemove.…We'll call the event handler controlSound.…Now there's no point in continuing to track…the mouse movement when no tone is being generated.…So what I'm going to do is I'm going to copy this line here…and then paste it into the stopTone function,…and change addEventListener to removeEventListener.…
So we now need to define the controlSound function.…So let's scroll down a bit…and then function controlSound.…We need to capture the event object,…so I'm going to pass (e) as the argument to controlSound.…
David introduces challenges and provides an overview of his solutions in PHP. Challenges include topics such as statistical analysis, searching directories for images, and accessing peripheral devices.
Visit other courses in the series to see how to solve the exact same challenges in languages like C#, C++, Java, Python, and Ruby.
Skill Level Intermediate
Q: I'm encountering script errors message with the prime_dates.php file used in the "Priming the date_record column" movie in this course. How can I resolve these errors?
A: To avoid script errors, use bindValue() instead of bindParam() in
Line 9 of the prime_dates.php file. You can also download the latest
copy of the exercise files, which corrects this issue for you. For a
more in-depth explanation of the difference between bindValue() and
bindParam(), check out the "Binding input and output values" video (http://www.lynda.com/PHP-
Q: Why can't I access the Lake Pend Orielle site (http://lpo.dt.navy.mil)?
A: The Lake Pend Orielle site is not accessible in some geographical areas. We have contacted the owner of the server to try to resolve this issue.
Q: I am unable to access the Lake Pend Oreille data from outside the U.S.
A: A static copy of this data is provided here for lynda.com members outside of the U.S
Problem One: Statistical Analysis
Problem Two: Image Analysis
Problem Three: Eight Queens
Problem Four: Accessing Peripherals
Problem Five: Recursion and Directories
Problem Six: Building the Web
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