Question

if语句为swipeDirection和swipeLength提供了正确的信息，除了图像更改外，我还获得了IF和ELSE的结果。

if ( (swipeDirection = 'down') && (swipeLength >= 180) ) {
                 touchEnabledElement.style.backgroundimage = 'railroadtracks.png';
                 document.getElementById('message').innerHTML = "IF" + 'Start H:' + startX + ' V:' + startY + '<br>' +  ' End H:' + curX + ' V:' + curY  + '<br>' + "Swipe Length: " + swipeLength + '<br>' + 'Swipe Angle: ' + swipeAngle + '&deg;' + '<br>' + 'Swipe Direction: ' + swipeDirection  + '<br><br><span style="font-size:.5em;">(Please wait for green screen before swiping again)<\/span>';
            } else {
                document.getElementById('message').innerHTML = "ELSE" + 'Start H:' + startX + ' V:' + startY + '<br>' +  ' End H:' + curX + ' V:' + curY  + '<br>' + "Swipe Length: " + swipeLength + '<br>' + 'Swipe Angle: ' + swipeAngle + '&deg;' + '<br>' + 'Swipe Direction: ' + swipeDirection  + '<br><br><span style="font-size:.5em;">(Please wait for green screen before swiping again)<\/span>';
                 touchEnabledElement.style.backgroundimage = 'railroadtracks2.png';

Answer 1

尝试.backgroundImage（注意：资本“我”）

Answer 2

该属性为backgroundImage而非backgroundimage，CSS中的网址语法为url(railroadtracks.png)，而不仅仅是railroadtracks.png

Answer 3

你在这里分配（=）而不是比较（==）：

if ( (swipeDirection = 'down') && (swipeLength >= 180) ) {

Answer 4

您的意思是swipeDirection = 'down'代替swipeDirection == 'down'吗？

jquery if语句不会改变背景图像

4 个答案: