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javascript - 如何根据条件更改轮播中的背景颜色

问题描述

我想更改价格低于 500 英镑的轮播元素的背景颜色。我需要在 JavaScript DOM 中执行此操作，但似乎没有任何效果......这是我到目前为止的想法：

// Get the elements- price and each carousel element

let price = document.getElementsByClassName("price");
let greenBackground = document.getElementsByClassName("close")[0];

//Prices are given as strings so I tried to convert it to a number to be able to compare

let priceAsNumber = parseInt(price, 10); 

//and finally I tried to apply the condition to change the background color

function changeBackground () {
  if (priceAsNumber <= 500) {
  document.greenBackground.style.background = #81CA81; 
  }
};

changeBackground();

我是初学者，所以代码可能会丢失很多，但我真的很感激一些提示来实现结果！

这是一个html示例：

<div class="owl-stage-outer"><div class="owl-stage" style="transform: translate3d(0px, 0px, 0px); transition: all 0s ease 0s; width: 2446px;"><div class="owl-item active" style="width: 152.857px;"><li class="all-months close selected"><label class="date-price-holidays">All Holidays<input type="radio" id="filter60_24" name="filter60" value="24" data-filter="24" data-compare="== 24 &amp;&amp; r.matchFlights[jvh.search.settings.currentMonth] &gt;= jvh.search.settings.currentAirportId &amp;&amp; &#39;24&#39; == " data-no="50" data-type="groupTxt" data-pos="-1" class="noautostyle filter-active" data-name-value="month" checked="checked" data-no-remember-notification="true"><span><span class="count">516</span> <span>found</span></span></label></li></div><div class="owl-item active" style="width: 152.857px;"><li class="close">
                                <label class="date-price-holidays">
                                    <span class="month">Mar<span class="year">2020</span></span>
                                    <input type="radio" id="filter60_2" name="filter60" value="2" data-filter=" r.matchFlights[jvh.search.settings.currentMonth] &gt;= jvh.search.settings.currentAirportId &amp;&amp; r.sale[jvh.search.settings.currentMonth]" data-compare="&gt; 0" data-no="50" data-type="groupTxt" data-pos="2" class="noautostyle" data-name-value="month" data-no-remember-notification="true">
                                    <span class="count-and-price"><span class="count">2</span> <span class="holidays">holidays</span><span class="from"> from </span><span class="price">£629<span class="pp">pp</span></span></span>
                                </label>
                            </li></div><div class="owl-item active" style="width: 152.857px;"><li class="close">
                                <label class="date-price-holidays">
                                    <span class="month">Apr<span class="year">2020</span></span>
                                    <input type="radio" id="filter60_3" name="filter60" value="3" data-filter=" r.matchFlights[jvh.search.settings.currentMonth] &gt;= jvh.search.settings.currentAirportId &amp;&amp; r.sale[jvh.search.settings.currentMonth]" data-compare="&gt; 0" data-no="50" data-type="groupTxt" data-pos="3" class="noautostyle" data-name-value="month" data-no-remember-notification="true">
                                    <span class="count-and-price"><span class="count">105</span> <span class="holidays">holidays</span><span class="from"> from </span><span class="price">£249<span class="pp">pp</span></span></span>
                                </label>
                            </li></div><div class="owl-item active" style="width: 152.857px;"><li class="close">
                                <label class="date-price-holidays">
                                    <span class="month">May<span class="year">2020</span></span>
                                    <input type="radio" id="filter60_4" name="filter60" value="4" data-filter=" r.matchFlights[jvh.search.settings.currentMonth] &gt;= jvh.search.settings.currentAirportId &amp;&amp; r.sale[jvh.search.settings.currentMonth]" data-compare="&gt; 0" data-no="50" data-type="groupTxt" data-pos="4" class="noautostyle" data-name-value="month" data-no-remember-notification="true">
                                    <span class="count-and-price"><span class="count">450</span> <span class="holidays">holidays</span><span class="from"> from </span><span class="price">£289<span class="pp">pp</span></span></span>
                                </label>
                            </li></div><div class="owl-item active" style="width: 152.857px;"><li class="close">
                                <label class="date-price-holidays">
                                    <span class="month">Jun<span class="year">2020</span></span>
                                    <input type="radio" id="filter60_5" name="filter60" value="5" data-filter=" r.matchFlights[jvh.search.settings.currentMonth] &gt;= jvh.search.settings.currentAirportId &amp;&amp; r.sale[jvh.search.settings.currentMonth]" data-compare="&gt; 0" data-no="50" data-type="groupTxt" data-pos="5" class="noautostyle" data-name-value="month" data-no-remember-notification="true">
                                    <span class="count-and-price"><span class="count">402</span> <span class="holidays">holidays</span><span class="from"> from </span><span class="price">£559<span class="pp">pp</span></span></span>
                                </label>

标签： javascriptdomcarouselbackground-colorowl-carousel

解决方案

当您使用时，let price = document.getElementsByClassName("price");您将收到一个 HTMLCollection 对象。

我的建议：如果您只想使用一个元素，querySelector 如下所示：

let price = document.querySelector('.price');
let greenBackground = document.getElementsByClassName('.close');

所以在这里你会收到 DOM 元素对象。然后你应该先得到它的值，然后再解析它。

let priceAsNumber = parseInt(price.innerText, 10);

所以，整个解决方案应该如下所示：

let price = document.querySelector('.price');
let greenBackground = document.getElementsByClassName('.close');
let priceAsNumber = parseInt(price.innerText, 10);
function changeBackground () {
  if (priceAsNumber <= 500) {
     document.greenBackground.style.background = #81CA81; 
  }
};
changeBackground();

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