A jQuery function used to check if a html element's parent div has a light background-color (or "background").

README.md

How to use:

1st: Make sure jQuery is included in your code

2nd:Include the script where in your code after jQuery has been included.

3rd: $('#colorful-element').parentHasLightBgColor();

jquery.parentHasLightBgColor.js

/**
 * This function is used to check if an element's parent div has a light "background color" (or "background").
 *
 * This is an adaptation of the larryfox's code: https://gist.github.com/larryfox/1636338.
 **/
(function($){
  
  $.fn.parentHasLightBgColor = function(){
    var r, g, b, hsp,
    	parentBgColor = this.parent().css('background-color');
    
    if(parentBgColor) {
	    if (parentBgColor.match(/^rgb/)) {
	      parentBgColor = parentBgColor.match(/^rgba?\((\d+),\s*(\d+),\s*(\d+)(?:,\s*(\d+(?:\.\d+)?))?\)$/);
	      r = parentBgColor[1];
	      g = parentBgColor[2];
	      b = parentBgColor[3];
	    } else {
			/* use Jed's alg for gathering the backgroud of the parent element:
			http://gist.github.com/983661*/
			parentBgColor = +("0x" + parentBgColor.slice(1).replace( 
			  parentBgColor.length < 5 && /./g, '$&$&')
			);

			// extract the r, g, and b values from the parent element's background color
			r = parentBgColor >> 16;
			g = parentBgColor & 255;
			b = parentBgColor >> 8 & 255;
			
	    }

	    // Use the HSP equation from http://alienryderflex.com/hsp.html
	    hsp = Math.sqrt( 
	      0.299 * (r * r) +
	      0.587 * (g * g) +
	      0.114 * (b * b)
	    );

	    /*use the hsp from above to check if the parent element 
	    has a light or dark background color*/
	    if (hsp > 127.5) {
	    	//the parent of this element is light
	      	return true;
	    } else {
			//the parent of this element is dark
			return false;
	    }
	}

	//return -1 so the default can be handled appropriately
	return -1;
  }
})(jQuery);

License.txt

DO WHATEVER YOU WANT TO PUBLIC LICENSE
Version 2, December 2004

 Copyright (C) 2016 Lincoln W Daniel <http://lincolnwdaniel.com>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.