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.
![7 Essential JavaScript Functions]()
I remember the early days of JavaScript where you needed a simple function for just about everything because the browser vendors implemented features differently, and not just edge features, basic features, like addEventListener and attachEvent. Times have changed but there are still a few functions each developer should...
![5 Ways that CSS and JavaScript Interact That You May Not Know About]()
CSS and JavaScript: the lines seemingly get blurred by each browser release. They have always done a very different job but in the end they are both front-end technologies so they need do need to work closely. We have our .js files and our .css, but...
![Create Classy Inputs Using MooTools’ OverText]()
The MooTools More library is a goldmine. A treasure chest. Pirates booty, if you will (and, of course, I will). More is full of plugins that add a lot of class and functionality to your website with minimal effort.
![Facebook Open Graph META Tags]()
It's no secret that Facebook has become a major traffic driver for all types of websites. Nowadays even large corporations steer consumers toward their Facebook pages instead of the corporate websites directly. And of course there are Facebook "Like" and "Recommend" widgets on every website. One...
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.