PHP Form Submission: Recognize Image Input Buttons
As you probably know, you can recognize a form submission from a "submit" input type by placing the following code in the "processing" PHP script:
if(isset($_POST['submit'])) { /* do stuff */ }
Did you know, however, that when using an "image" input type to submit the form, the above wont work? You need to add a "_x" to the field name in PHP:
if(isset($_POST['submit_x'])) { /* do stuff */ }
Odd, huh? This works the same when using a form "GET" method.
![9 Mind-Blowing Canvas Demos]()
The <canvas> element has been a revelation for the visual experts among our ranks. Canvas provides the means for incredible and efficient animations with the added bonus of no Flash; these developers can flash their awesome JavaScript skills instead. Here are nine unbelievable canvas demos that...
![Write Better JavaScript with Promises]()
You've probably heard the talk around the water cooler about how promises are the future. All of the cool kids are using them, but you don't see what makes them so special. Can't you just use a callback? What's the big deal? In this article, we'll...
![PHP / MooTools 1.2 Accordion Helper]()
The MooTools Accordion plugin seems to be the plugin that people seem to have the most problems with. It's an awesome plugin, so I can see why so many people want to use it, but I think that may be part of the problem.
![spellcheck Attribute]()
Many useful attributes have been provided to web developers recently: download, placeholder, autofocus, and more. One helpful older attribute is the spellcheck attribute which allows developers to control an elements ability to be spell checked or subject to grammar checks. Simple enough, right?
The _x and _y represent the coordinate location you clicked the image at.
Think this is only an issue with IE.
Yeah. The _x- and _y-coordinates are great for improving the security of a form! I’ve used this to determine if the form has been filled by a human. A spam-bot won’t submit any coordinates but a human has to click on the button and so there will always be coordinates (you’ll have to deactive submitting with the ENTER-button).
@Matthias: Good point on the security enhancement — I’ve never though of that!
@ Matthias
Thanks for posting your comment. I think telling the user that the ENTER button has been deactivated for bot protection is easier than having the user type in a captcha.
I’ll definitely be looking into that method and most likely incorporating it into my projects.
@Braxo – Wait – “Enter button” is deactivated? How would this affect someone who cannot use a mouse/relies on accessibility tools to fill out forms and the like?
Some sites cannot get away with it (coughtargetcough).
You can save yourself the trouble and just give the input a name attribute and check for that. Saves from changing code in two places (the input and the PHP submit validation).
<input type="image" src="image.png" name="submitted" value="Submit" />
I should clarify that…
It saves from changing code in 2 places should you want to change to/from an image submit or a standard submit.