Invert Selection (Toggle Selection) Checkboxes & Radio Buttons (HTML forms)

Uses jQuery & JavaScript to select the opposite of any checkboxes that are currently selected

Live Demo

This uses PHP, but you can simply view page source to get a pure HTML version

jQuery Functions

• Invert Current Selection (checkboxes only)
• Select All
• Select None

Select None works to deselect radio buttons
This is for mutually exclusive choices, but when the entire is question optional & you want no response to be valid
The other 2 functions can be used on radio buttons, but aren't effective since radio buttons are mutually exclusive.
Results in the last radio button being selected
It doesn't break anything, just doesn't work as intended

No CSS just to make things easier to understand
Possible improvements could be styling the buttons

Code Details & Usage

jQuery Functions (General Usage)

• jQuery functions work by taking in an input parameter which is the name attribute of an HTML input tag
  This should be the name for a group of elements
  The action to select all, none, or invert is only performed on that group You should create a new different set of buttons for each group where you want the functionality
• The name attribute of each checkbox in a group must have square brackets [] at the end <input type='checkbox' id='chk1' name='chkBoxes[]' value='1'>
<input type='checkbox' id='chk2' name='chkBoxes[]' value='2'>
  Notice the [] in name='chkBoxes[]'
  This puts an array of checkboxes in the $_POST array when the form is submitted, instead of individual checkboxes. (For easier processing)
• Read this article to learn about checkbox groups
• Radio buttons are mutually exclusive by design so no need for brackets [], just group them by having the same exact name attribute for a group
• An HTML button with an onClick event handler must be placed on the page near the checkboxes with the correct argument in the function call
  <input type="button" name="btnInvert" onclick="invert('chkBoxes[]')" value="Invert">
  This says:
  1. Call the invert() function when clicked
  2. Pass in the argument chkBoxes[]
  3. Only invert() the checkboxes in the group chkBoxes[]
• The only difference for selectAll() and selectNone() is the name of the function to call
• REMEMBER TO CHANGE THE INPUT PARAMETER TO THE FUNCTION FOR EACH SET OF BUTTONS YOU CREATE
  Otherwise clicking 1 buttong will affect multiple groups
•  
• jQuery functions set the property of an HTML input element using item.prop("checked", true); because item.attr('checked','checked'); doesn't work
  attr updates the HTML & you can see it happen in realtime using Inspect Element, but the actual page doesn't change
• selectAll simply adds element.prop("checked", true); to every element in a group regardless of its current state
  This guarantees all items in a group are checked & it doesn't hurt to set the property to true if it's already true
• selectNone is the opposite & simply sets the property to false
• The invert function checks if an input is checked (true/false) & sets the new property to the opposite of its previous state by negating true or false
•  
• USE selectNone ON RADIO BUTTONS TO "DE-SELECT" THE RADIO BUTTON ALTOGETHER, BUT invert & selectNone WON'T WORK FOR RADIO BUTTONS*

PHP Specific

• Form submits to itself
• Prints out the contents of the $_POST array (empty to start with since form isn't submitted)
• Uses a for loop to print checkboxes & labels (or just use the HTML version)

Previous Versions (failed attempts)

The attempts/ folder is a collections of my initial versions which didn't pan out

Tutorial Sources

I cobbled together my own invert() function based on various sources because none of them individually was exactly what I was looking for

• JQuery checkboxes inverse selection | Marko Jakic Probably the most help, but added to it & expanded compact if-else form
• Stack Overflow: javascript - Why is jQuery is not checking/unchecking checkbox finally figured out why adding checked wasn't actually updating the html
• Javascript-invert the CheckBoxe selection Older JavaScript method NOT using jQuery. 1st one I got to work at all, but didn't use much else
• jQuery Checkboxes: Select All, Select None, and Invert Selection A start, but not much help
• Stack Overflow: jQuery hasAttr checking to see if there is an attribute on an element some help on checkbox event handling, but not complete
• CSS-Tricks: A jQuery hasAttr() Equivalent testing if an an element has an attribute
• Stack Overflow: jQuery checkbox event handling helped when finding how to call functions
•  
• HTML Multi checkbox set - the correct way to group checkboxes | wasted potential