如何通过DOMAttrModified检测类更改

Question

我需要检测一些类更改,我使用这个DOMAttrModified,但有些东西是错的,什么？

var first_img = $('body').find('li:first').find('img');

first_img.on('DOMAttrModified',function(e){
    if (e.attrName === 'class') {
        if ($(this).hasClass('current-image')) {
            $(this).removeClass().addClass('previous-image');
        }
        console.log('log');
    }
});

感谢您的建议.

Answer 1

当前的问题是,attrName属性不是jQuery事件对象的一部分......您需要使用e.originalEvent.attrName.这是一个工作的例子:

var first_img = $("body").find("div").first();

first_img.on("DOMAttrModified", function (e) {
    if (e.originalEvent.attrName === "class") {
        console.log("##DOMAttrModified, class changed");
        if ($(this).hasClass("current-image")) {
            console.log("##Element has 'current-image' class, changing");
            $(this).removeClass().addClass("previous-image");
        }
    }
});

setTimeout(function () {
    first_img.addClass("current-image");
}, 1000);

演示: http ://jsfiddle.net/R5rTy/1/

这setTimeout是模拟随机发生的事件.

显然,DOMAttrModified所有浏览器都不支持该事件 - http://help.dottoro.com/ljfvvdnm.php#additionalEvents

更新:

使用较新的MutationObserver,以下显示了两种想法的使用:

var firstImg, observerConfig, firstImgObserver;

firstImg = $("body").find("div").first();
observerConfig = {
    attributes: true,
    childList: true,
    characterData: true
};
firstImgObserver = new MutationObserver(function (mutations) {
    mutations.forEach(function (mutation) {
        var newVal = $(mutation.target).prop(mutation.attributeName);
        if (mutation.attributeName === "class") {
            console.log("MutationObserver class changed to", newVal);
        } else if (mutation.attributeName === "id") {
            console.log("MutationObserver id changed to", newVal);
        }
    });
});

firstImgObserver.observe(firstImg[0], observerConfig);
// later, you can stop observing
//observer.disconnect();

firstImg.on("DOMAttrModified", function (e) {
    var newVal = $(this).prop(e.originalEvent.attrName);
    console.log("DOMAttrModified", e.originalEvent.attrName, "changed to", newVal);
});

setTimeout(function () {
    firstImg.addClass("previous-image").addClass("fdsa");
}, 1000);

演示: http ://jsfiddle.net/ybGCF/

参考:

• https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver