7

这似乎是一个简单的问题,但没有什么可以解决它。我正在尝试使用 javascript/jQuery 动态更改某些文本的背景颜色(从白色或粉红色到绿色),但由于某种原因它不起作用。文本使用名为“.novice”的 CSS 类设置样式。

这是CSS。这很简单。我也尝试过完全删除背景颜色,所以它还没有设置背景颜色。

<style type="text/css">
.novice {
background-color: pink;
}

</style>

这是一个包含我使用循环写出的项目的数组。第一项具有“新手”类

var achievements = ['<span class="novice">novice - 10 or more guesses </span>', ...]

下面是一个 if 语句,如果为真,则应该使“.novice”类具有“背景色:绿色”属性,并使“新手 - 10 次或更多猜测”以绿色突出显示。我很肯定我已经正确设置了变量 timeguessed 并且拼写正确。但是,当 timesguessed 大于 10 时,“新手...”仍然不会以绿色突出显示。

if (timesguessed > 10) {
    $('.novice').css('background-color', 'green'); 
}

我在上面输入这个部分对吗? 我也试过替换 $('.novice').css('background-color', 'green'); 与 $('.novice').background-color(green); ,尽管这可能是错误的。

即使我用所谓的新修改的“新手”类打印出另一行,文本仍然不会以绿色突出显示。

document.write('<span class="novice">novice - 10 or more guesses </span>'); 

我知道原始的 CSS .novice 类正在工作,因为无论时间猜测是大于还是小于 10,文本都会以粉红色突出显示。

我不确定Javascript是否没有修改CSS类,或者什么。或者,也许它只是有其他东西覆盖它?

谢谢您的帮助。是的,我是 javascript/jQuery 的初学者。

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<style type="text/css">
.novice {
}

</style>
<script type="text/javascript" src="../MM_JAVASCRIPT2E/MM_JAVASCRIPT2E/_js/jquery-1.6.3.min.js"></script>

<title>Number Guessing Game</title>


</head>

    <body>
    <h1 style="text-align:center;"> Number Game </br> Try to guess my number that is between 0-1000 </h1>
    <script>
// BEGIN LONG BLOCK OF CODE WITH GUESSING GAME MECHANISMS. You can ignore this part I think, this part works.
    var realnumber = prompt('Player 1, please enter a number for Player 2 to guess then hand it off to Player 2.', '');
    while (isNaN(realnumber)) {
        realnumber = prompt('Player 1, please enter a NUMBER, dimwit, for Player 2 to guess.', '');}
    var timesguessed=0;
    while (numbertoguess != 0) {
    var numbertoguess = prompt("Player 2, guess a number", "");
    while (isNaN(numbertoguess)) {
        numbertoguess = prompt('Please, type in a number');} // why don't I need an "else" here?
    numbertoguess = Math.abs(numbertoguess - realnumber);
        if ( numbertoguess >= 50 ) {
        alert("Tundra cold");
        timesguessed++;
        }
    else if ( 30 <= numbertoguess && numbertoguess < 50) {
        alert("cold");
        timesguessed++;
        }
    else if ( 20 <= numbertoguess && numbertoguess < 30 ) {
        alert("warm");
        timesguessed++;
        }
    else if ( 10 <= numbertoguess && numbertoguess< 20 ) {
        alert("hot");
        timesguessed++;
    }
    else if ( 5 <= numbertoguess && numbertoguess < 10 ) {
        alert("Steaming hot!");
        timesguessed++;
        }
    else if ( 3 <= numbertoguess && numbertoguess < 5 ) {
        alert("SCALDING HOT!");
        timesguessed++;
    }
    else if ( 1 < numbertoguess && numbertoguess < 3 ) {
        alert("FIRE!");
        timesguessed++;
    }
    else if ( numbertoguess == 1 ) {
        alert("Face Melting!");
        timesguessed++;
    } else if ( numbertoguess == 0 ) { 
        alert("BINGO!");
        timesguessed++;
    }
    }
    document.write('</br></br></br></br><h2 style="text-align:center; font-size: 18px;"> The number was ' + realnumber + '.');
    if (timesguessed == 1) {
        document.write('</span><h2 style="text-align:center;">It took you ' + timesguessed + ' guess.</h2>');
    } else {
    document.write('<h2 style="text-align:center;">It took you ' + timesguessed + ' guesses.</h2>');
    }

// END LONG BLOCK OF CODE WITH GUESSING GAME MECHANISMS


    document.write('</br></br>')
//below is the array written out with a loop
    var achievements = ['<span class="novice">novice - 10 or more guesses </span>',bronze - 7-10 guesses', 'silver', 'gold', 'titanium', 'platinum', 'diamond', ]
    var counter = 0;
        while (counter < achievements.length) {
        document.write('<h2 style="text-align:center;">' + achievements[counter] + ' ');
        counter++;
        }
//below is the "if" function of question
    if (timesguessed > 10) {
        $('.novice').css('background-color', '#00FF00'); //why does this not work?
    }
    document.write('<span class="novice">novice - 10 or more guesses </span>'); //why does this not work?

    </script>

    </body>
    </html>
4

3 回答 3

3

.css()在您的代码中,通过向它们添加内联样式来更改页面上已有元素的样式 -而不是通过修改 css 规则。

您可以在运行时添加新规则,如下所示:

$('head').append('<style type="text/css">.novice{color:green;}</style>'); 

不过,我不支持这种修改。我宁愿看到像这样的css

.novice {background-color: pink;}
.over-ten-guesses .novice {background-color:green;}

之后,您可以.over-ten-guesses在任何具有.novice其后代的容器元素上使用 Javascript 切换该类。

于 2012-07-05T03:56:01.953 回答
2

您可以通过以下方式进行 步骤 1

   var imageUrl= "URL OF THE IMAGE HERE";
   var BackgroundColor="RED"; // what ever color you want

对于具有相同类的元素

var elements = document.getElementsByClassName("ClassName")
            for (var i = 0; i < elements.length; i++) {
                elements[i].style.background=imageUrl; 
                //if you want to change bg image
                //if you want to change bg color
                elements[i].style.backgroundColor=BackgroundColor ;
            }

更改具有 ID 的元素

document.getElementById("ElementId").style.backgroundImage=imageUrl
document.getElementById("ElementId").style.backgroundColor=BackgroundColor 
于 2015-02-26T05:14:30.967 回答
0

jQuery 未正确包含在页面中。检查你的控制台会告诉你链接是否失败(并且应该说那$是未定义的)。要使用谷歌的最新版本,请使用此链接:http ://ajax.googleapis.com/ajax/libs/jquery/1.7/jquery.min.js

即改变这个:

<script type="text/javascript" src="../MM_JAVASCRIPT2E/MM_JAVASCRIPT2E/_js/jquery-1.6.3.min.js"></script>

对此

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7/jquery.min.js"></script>

在未定义的对象上调用方法会导致错误,并且后续代码的执行将失败。

于 2012-07-05T03:51:26.473 回答