使用javascript/jQuery更改类的background-color属性

Laz*_*rks 6 javascript css jquery class background-color

这似乎是一个简单的问题,但没有什么能解决它.我试图用javascript/jQuery动态地改变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.该文本使用名为".novice"的CSS类进行样式设置.

这是CSS.这很简单.我也尝试完全删除背景颜色,因此它还没有设置背景颜色.

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

</style>
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这是一个数组,其中包含我使用循环写出的项目.第一项有"新手"类

var achievements = ['<span class="novice">novice - 10 or more guesses </span>', ...]
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下面是一个if语句,如果为true,则应该使".novice"类具有"background-color:green"属性,并使"新手 - 10个或更多猜测"以绿色突出显示.我很肯定我已经正确设置了变量timeguessed并拼写正确.但是,当时间推测大于10时,"新手......"仍然不会以绿色突出显示.

if (timesguessed > 10) {
    $('.novice').css('background-color', 'green'); 
}
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我输入上面这部分了吗? 我也试过替换$('.novice').css('background-color','green'); with $('.novice').background-color(green); 虽然这可能是错的.

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>'); 
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我知道原来的CSS .novice类正在工作,因为如果时间间隔大于或小于10,文本将以粉红色突出显示.

我不确定Javascript是不是在修改CSS类,或者是什么.或者它可能只是其他东西覆盖它?

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>
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nbr*_*oks 0

jQuery 未正确包含在页面中。检查控制台会告诉您链接是否失败(并且还应该说链接$未定义)。要使用 google 的最新版本,请使用以下链接: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>
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对此

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