//获取RGB值 颜色深用白色 颜色浅则用黑色

var RgbValue = http://www.mamicode.com/this.style.backgroundColor.replace("rgb(", "").replace(")", "");

var RgbValueArry = RgbValue.split(",");

var $grayLevel = RgbValueArry[0] * 0.299 + RgbValueArry[1] * 0.587 + RgbValueArry[2] * 0.114;

$this.addClass("color_curr");

if ($grayLevel >= 192) {
　　$this.html(‘<p class="fa fa-check color_black"></p>‘);
} else {
　　$this.html(‘<p class="fa fa-check color_withe"></p>‘);
}

js 判断颜色是否为深色 阀值