Javascript onclick、onmouseout 冲突、循环

Question

我是新来的，这是我在 stackflow 中的第一次“询问”:)这是我的代码。 主要思想是:

1. 图标默认为白色
   
2. mouseover 和 mouseout，它们一起工作就像 css 中的“hover”。我无法在 css 中使用悬停，因为图像是 .png，因此必须使用 js。
   
3. 图标 onclick 变为灰色，看起来像是已激活。

尽管我以一种不聪明的方式使它变得非常复杂，但该代码仍然有效。有什么办法可以让它变得更简单吗？使用循环？？但如何呢？提前致谢!

var clickedWalk = false;
var clickedBicycle = false;
var clickedCar = false;
var clickedBus = false;
var clickedParkAndRide = false;

function mouseOverWalk() {
    document.getElementById("walk").src="images/Walk-gray.png";
}

function mouseOverBicycle() {
    document.getElementById("bicycle").src="images/Biking-gray.png";
}

function mouseOverCar() {
    document.getElementById("car").src="images/Car-gray.png";
}

function mouseOverBus() {
    document.getElementById("bus").src="images/Bus-gray.png";
}

function mouseOverParkAndRide() {
    document.getElementById("park-and-ride").src="images/PPlusBus-gray.png";
}



function mouseOutWalk() {
    if (clickedWalk == false) {
        document.getElementById("walk").src = "images/Walk.png"; //mouseout works
    }
    clickedWalk = false;      
}

function mouseOutBicycle() {
    if (clickedBicycle == false) { //no click
        document.getElementById("bicycle").src = "images/Biking.png"; //mouseout works
    }
    clickedBicycle = false;
}

function mouseOutCar() {
    if (clickedCar == false) { //no click
        document.getElementById("car").src = "images/Car.png"; //mouseout works
    }
    clickedCar = false;
}

function mouseOutBus() {
    if (clickedBus == false) { //no click
        document.getElementById("bus").src = "images/Bus.png"; //mouseout works
    }
    clickedBus = false;
}

function mouseOutParkAndRide() {
    if (clickedParkAndRide == false) { //no click
        document.getElementById("park-and-ride").src = "images/PPlusBus.png"; //mouseout works
    }
    clickedParkAndRide = false;
}

function clickWalk() {
    document.getElementById("walk").src="images/Walk-gray.png";  //gray
    document.getElementById("bicycle").src="images/Biking.png"; //white
    document.getElementById("car").src="images/Car.png"; //white
    document.getElementById("bus").src="images/Bus.png"; //white
    document.getElementById("park-and-ride").src="images/PPlusBus.png"; //white
    
    clickedWalk = true;
}

function clickBicycle() {
    
    document.getElementById("walk").src="images/Walk.png"; //white
    document.getElementById("bicycle").src="images/Biking-gray.png"; //gray
    document.getElementById("car").src="images/Car.png"; //white
    document.getElementById("bus").src="images/Bus.png"; //white
    document.getElementById("park-and-ride").src="images/PPlusBus.png"; //white
    
    clickedBicycle = true;
}

function clickCar() {
    document.getElementById("walk").src="images/Walk.png"; //white
    document.getElementById("bicycle").src="images/Biking.png"; //white
    document.getElementById("car").src="images/Car-gray.png"; //gray
    document.getElementById("bus").src="images/Bus.png"; //white
    document.getElementById("park-and-ride").src="images/PPlusBus.png"; //white

    clickedCar = true;
}

function clickBus() {
    document.getElementById("walk").src="images/Walk.png"; //white
    document.getElementById("bicycle").src="images/Biking.png"; //white
    document.getElementById("car").src="images/Car.png"; //white
    document.getElementById("bus").src="images/Bus-gray.png"; //gray
    document.getElementById("park-and-ride").src="images/PPlusBus.png"; //white

    clickedBus = true;
}

function clickParkAndRide() {
    document.getElementById("walk").src="images/Walk.png"; //white
    document.getElementById("bicycle").src="images/Biking.png"; //white
    document.getElementById("car").src="images/Car.png"; //white
    document.getElementById("bus").src="images/Bus.png"; //white
    document.getElementById("park-and-ride").src="images/PPlusBus-gray.png"; //gray

    clickedParkAndRide = true;
}

<div id="modeListBoxSelect">
        <ul>
            <li onclick="travelMode.byWalk()"><img id="walk" onmouseover="mouseOverWalk()" onmouseout="mouseOutWalk()" onclick="clickWalk()" src="images/Walk.png" alt="walk"</li>
            <li onclick="travelMode.byBike()"><img id="bicycle" onmouseover="mouseOverBicycle()" onmouseout="mouseOutBicycle()" onclick="clickBicycle()" src="images/Biking.png" alt="bicycle"</li>
            <li onclick="travelMode.byCar()"><img id="car" onmouseover="mouseOverCar()" onmouseout="mouseOutCar()" onclick="clickCar()" src="images/Car.png" alt="car"</li>
            <li onclick="travelMode.byBus()"><img id="bus" onmouseover="mouseOverBus()" onmouseout="mouseOutBus()" onclick="clickBus()" src="images/Bus.png" alt="bus"</li>
            <li onclick="travelMode.byParkAndRide()"><img id="park-and-ride" onmouseover="mouseOverParkAndRide()" onmouseout="mouseOutParkAndRide()" onclick="clickParkAndRide()" src="images/PPlusBus.png" alt="park-and-ride"</li>
        </ul>
    </div>

Answer 1

实际上，您可以在CSS中使用“hover”。简单地说，将“li”设置为具有适当高度和宽度的 block 元素，并向其添加“id”属性，就像对“img”所做的那样。 然后删除“img”元素并使用 css 来设置“li”的样式。

<div id="modeListBoxSelect">
    <ul>
        <li onclick="travelMode.byWalk()" id="walk"></li>
    </ul>
</div>

和CSS:

#walk {
display: block;
width: XXXpx;
height: YYYpx; // size of the image
background-image: url('your-image.png');
}
#walk:hover {
background-image: url('your-image-after-hover.png');
}