javascript - 如何使用按钮更改网页上的字体颜色？

Question

我想知道是否有人可以告诉我如何在用户单击按钮时更改网页的字体颜色。

我有背景功能，但它似乎不适用于文本。

到目前为止，这是我的代码:

<div class="dropdown">
<button onclick="toggleBackgroundDropdown()" 
class="dropdownButton">Background</button>
<div id="backgroundDropdown" class="backgroundDropdown">
<a class="colorbutton">Red</a>
<a class="colorbutton">Yellow</a>
<a class="colorbutton">Blue</a>
<a class="colorbutton">White</a>
</div>

<button onclick="toggleTextColorDropdown()" class="dropdownButton">Text 
Color</button>
<div id="textColorDropdown" class="textColorDropdown">
<a class="textcolorbutton">Red</a>
<a class="textcolorbutton">Yellow</a>
<a class="textcolorbutton">Blue</a>
<a class="textcolorbutton">White</a>
</div>

</div>

<script>
function toggleBackgroundDropdown() 
{   
document.getElementById("backgroundDropdown").classList.toggle("show");
}

function toggleTextColorDropdown() 
{   
document.getElementById("textColorDropdown").classList.toggle("show");
}

function changeColor()
{
var x = event.clientX; 
var y = event.clientY;
var elementMouseIsOver = document.elementFromPoint(x, y);

document.body.style.backgroundColor = elementMouseIsOver.text;
}

function changeTextColor()
{
var x = event.clientX; 
var y = event.clientY;
var elementMouseIsOver = document.elementFromPoint(x, y);

var a = document.getElementById('a');
a.style.color = elementMouseIsOver.text;
}

window.onload = function(event)
{
var colorbuttons = document.getElementsByClassName("colorbutton");
for (var i = 0; i < colorbuttons.length; i++) 
{   
    colorbuttons[i].addEventListener('click', changeColor, false);
}

var textcolorbuttons = document.getElementsByClassName("textColorButton");
for (var i = 0; i < textcolorbuttons.length; i++) 
{   
    textcolorbuttons[i].addEventListener('click', changeTextColor, false);
}
}

window.onclick = function(event)
{
if (event.target.className == "colorbutton")
{
    toggleBackgroundDropdown();
}
else if (event.target.className == "textcolorbutton")
{
    toggleTextColorDropdown();
}
}
</script>

Answer 1

为按钮提供一个唯一的 id，例如为按钮提供 backgroundChange。然后使用下面的代码

$("#backgroundChange").click(function(){
   if($(this).css('background-color')=='lightgrey')
         $(this).css('background-color', 'red');
   else {
         $(this).css('background-color', 'lightgrey);
   }
});

同样你可以切换类

$("#backgroundChange").click(function () {
        $(this).toggleClass('backgroundDropdown');
});