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x3k
Asked: 2020-06-14 04:58:43 +0800 CST 2020-06-14 04:58:43 +0800 CST

What does the jQuery selector $({}) do?

  • 772

I am making an animation and I have found the following pen: CodePen

Code of pen:

$({percentage: 0}).stop(true).animate({percentage: value}, {
    duration : 2000,
    easing: "easeOutExpo",
    step: function () {
        // percentage with 1 decimal;
        var percentageVal = Math.round(this.percentage * 10) / 10;

        $el.text(percentageVal + '%');
    }
})

Selector:

$({percentage: 0}).stop(true).animate({percentage: value}, {...});

  • That changes?
  • What is it for?
  • In case of specifying properties of jQuery, what does the of percentage?

I suppose it jquerywill have a JSONproperties and they will be changed in this way, but I had not seen it before.

jquery

1 Answers

  1. Best Answer

    $({percentage: 0})It is the context in which the animation will work and when you indicate what the property is in the method animate(), it will look for the indicated property on the context and apply the animation to it.

    If you look closely, you will notice how the body of step()is used thisto access the property porcentagedefined in the object passed by the jquery constructor, which is the context:

     step: function () {
             // accediendo al contexto provisto en el constructor de jquery
                                        ↓
        var percentageVal = Math.round(this.percentage * 10) / 10;

        $el.text(percentageVal + '%');
    }

    TL;DR {percentage: 0} represents the context sent to the jquery constructor. .animate({percentage: value},{})represents the property to animate based on the context.

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