如何在点击 <a> 标签时更改 CSS 链接

How to change CSS link on click of <a> tag?

本文关键字：标签 链接 CSS      更新时间：2023-09-26

我已经尝试了几个小时来让我的锚标签工作，如果单击，它会更改指向颜色主题 CSS 的链接href。

这是我到目前为止得到和发现的。我只是想把它改成红色主题。

HTML（删除列表标记之间的空格，以防止inline-block导致视觉对象出现间隙）

<header>
  <ul>
   <li>
    <a id="theme_selector_red" href="" onclick="applyCSS('css/theme_red.css');"></a>
   </li>
   <li>
    <a id="theme_selector_green" href=""></a>
   </li>
   <li>
    <a id="theme_selector_blue" href=""></a>
   </li>
  </ul>
 </header>

链接标记

<link id="color_theme" type="text/css" rel="stylesheet" href="css/theme_blue.css">

JavaScript我以不同的方式尝试了.attr（），也尝试删除和重置属性，但没有运气。警报只是为了测试单击是否进入该功能，是的，每次我单击链接时，网站都会显示警报。

function applyCSS(css_link){
   $('#color_theme').attr("href", css_link);
   document.getElementById('color_theme').removeAttribute('href');
   document.getElementById('color_theme').setAttribute('href', css_link);
   alert('hey');
};
链接

标签有效，只是当我单击链接时它不会改变它href。 :(

将 onclick 更改为：

onclick="applyCSS('css/theme_red.css'); return false;"

目前，运行 applyCSS 后，它会跟随链接并刷新页面。"返回 false"将阻止该行为。

这是向您展示如何做到这一点的示例，它很棒，因为即使刷新它也会停留在您选择的最后一个主题上

<html>
<head>
<link href="style1.css" media="all" rel="stylesheet" type="text/css" />
<link href="style2.css" media="screen" rel="alternate stylesheet" title="style2" type="text/css" />
<link href="style3.css" media="screen" rel="alternate stylesheet" title="style3" type="text/css" />
<script src="BCo.js" type="text/javascript"></script>
</head>
<body>
<ul>
<li>
<a href="javascript:chooseStyle('style1',60)" target="_self" >1</a>
</li>
<li>
<a href="javascript:chooseStyle('style2',60)" target="_self" >2</a>
</li>
<li>
<a href="javascript:chooseStyle('style3',60)" target="_self">3</a>
</li>
</ul>
<h1>test</h1>
</body>
</html>

这是 js 文件 BCo 的代码.js

var manual_or_random="manual" //"manual" or "random"
var randomsetting="3 days" //"eachtime", "sessiononly", or "x days (replace x with desired integer)". Only applicable if mode is random.
//////No need to edit beyond here//////////////
function getCookie(Name) { 
var re=new RegExp(Name+"=[^;]+", "i"); //construct RE to search for target name/value pair
if (document.cookie.match(re)) //if cookie found
return document.cookie.match(re)[0].split("=")[1] //return its value
return null
}
    function setCookie(name, value, days) {
var expireDate = new Date()
//set "expstring" to either future or past date, to set or delete cookie, respectively
var expstring=(typeof days!="undefined")? expireDate.setDate(expireDate.getDate()+parseInt(days)) : expireDate.setDate(expireDate.getDate()-5)
document.cookie = name+"="+value+"; expires="+expireDate.toGMTString()+"; path=/";
}
function deleteCookie(name){
setCookie(name, "moot")
}

function setStylesheet(title, randomize){ //Main stylesheet switcher function. Second parameter if defined causes a random alternate stylesheet (including none) to be enabled
var i, cacheobj, altsheets=[""]
for(i=0; (cacheobj=document.getElementsByTagName("link")[i]); i++) {
if(cacheobj.getAttribute("rel").toLowerCase()=="alternate stylesheet" && cacheobj.getAttribute("title")) { //if this is an alternate stylesheet with title
cacheobj.disabled = true
altsheets.push(cacheobj) //store reference to alt stylesheets inside array
if(cacheobj.getAttribute("title") == title) //enable alternate stylesheet with title that matches parameter
cacheobj.disabled = false //enable chosen style sheet
}
}
if (typeof randomize!="undefined"){ //if second paramter is defined, randomly enable an alt style sheet (includes non)
var randomnumber=Math.floor(Math.random()*altsheets.length)
altsheets[randomnumber].disabled=false
}
return (typeof randomize!="undefined" && altsheets[randomnumber]!="")? altsheets[randomnumber].getAttribute("title") : "" //if in "random" mode, return "title" of randomly enabled alt stylesheet
}
function chooseStyle(styletitle, days){ //Interface function to switch style sheets plus save "title" attr of selected stylesheet to cookie
if (document.getElementById){
setStylesheet(styletitle)
setCookie("mysheet", styletitle, days)
}
}
function indicateSelected(element){ //Optional function that shows which style sheet is currently selected within group of radio buttons or select menu
if (selectedtitle!=null && (element.type==undefined || element.type=="select-one")){ //if element is a radio button or select menu
var element=(element.type=="select-one") ? element.options : element
for (var i=0; i<element.length; i++){
if (element[i].value==selectedtitle){ //if match found between form element value and cookie value
if (element[i].tagName=="OPTION") //if this is a select menu
element[i].selected=true
else //else if it's a radio button
element[i].checked=true
break
}
}
}
}
if (manual_or_random=="manual"){ //IF MANUAL MODE
var selectedtitle=getCookie("mysheet")
if (document.getElementById && selectedtitle!=null) //load user chosen style sheet from cookie if there is one stored
setStylesheet(selectedtitle)
}
else if (manual_or_random=="random"){ //IF AUTO RANDOM MODE
if (randomsetting=="eachtime")
setStylesheet("", "random")
else if (randomsetting=="sessiononly"){ //if "sessiononly" setting
if (getCookie("mysheet_s")==null) //if "mysheet_s" session cookie is empty
document.cookie="mysheet_s="+setStylesheet("", "random")+"; path=/" //activate random alt stylesheet while remembering its "title" value
else
setStylesheet(getCookie("mysheet_s")) //just activate random alt stylesheet stored in cookie
}
else if (randomsetting.search(/^[1-9]+ days/i)!=-1){ //if "x days" setting
if (getCookie("mysheet_r")==null || parseInt(getCookie("mysheet_r_days"))!=parseInt(randomsetting)){ //if "mysheet_r" cookie is empty or admin has changed number of days to persist in "x days" variable
setCookie("mysheet_r", setStylesheet("", "random"), parseInt(randomsetting)) //activate random alt stylesheet while remembering its "title" value
setCookie("mysheet_r_days", randomsetting, parseInt(randomsetting)) //Also remember the number of days to persist per the "x days" variable
}
else
setStylesheet(getCookie("mysheet_r")) //just activate random alt stylesheet stored in cookie
} 
}

另外，如果您想快速检查这里是 style1.css 和 style2 的代码.css

样式1.css代码

h1 {
font-family: Tahoma,arial;
font-size: 18px;
font-weight: bold;
line-height: 20px;
color: #1D828C;
}

样式2.css代码

h1 {
color: #7c7c7c;
}

你可以简单地使用Css，你可以在这个链接中找到它，

.HTML：

<a href="#" tabindex="1">Stays blue</a>

.CSS：

a {   
    color: black;   
}
a:active {
    color: blue;
}
a[tabindex]:focus {
    color:blue;
    outline: none;
}

你可以尝试一个PHP方法。

switch ($theme) {
  case 'red':
  $theme_file = 'red.css';
  break;
  case 'blue':
  $theme_file = 'blue.css';
  break;
  default:
  $theme_file = 'red.css';
}

然后使用HTML，您所需要的只是：

<a href="?theme=red">Red</a>
<a href="?theme=blue">Blue</a>

如果可以使用此方法设置 cookie，以便在用户返回时记住主题，或者如果您正在使用数据库，则可以永久存储它。

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