Many people who have been exposed to HTML and CSS programming will use JavaScript to interact with web pages. Among them, click events are the most common interaction method. Through click events, we can operate on elements in the web page, such as changing the style of the element (CSS), or triggering certain functions. Next, let's take a look at how to change CSS through click events.

1. Basic knowledge of HTML and CSS

Before understanding how click events change CSS, we need to master the basic knowledge of HTML and CSS. HTML is a markup language mainly used to create web pages. It consists of a series of tags (Tags). Tags wrap various elements in web pages, such as text, images, links, etc. For example, the following HTML code:

     
  
欢迎来到我的网页
  

In the above code,8b05045a5be5764f313ed5b9168a17e6declares the file type as HTML,100db36a723c770d327fc0aef2ce13b1wraps the entire For web pages, the93f0f5c25f18dab9d176bd4f6de5d30etag contains some metadata of the web page, such as title, style, etc. Theb2386ffb911b14667cb8f0f91ea547a7tag defines the title of the web page, and thec9ccee2e6ea535a969eb3f532ad9fe89tag defines the style of the h1 element (the font color is red). The6c04bd5ca3fcae76e30b72ad730ca86dtag contains the main content of the webpage, including a4a249f0d628e2318394fd9b75b4636b1tag, which displays the text "Welcome to my webpage".

CSS (Cascading Style Sheets) is a style sheet language, mainly used to define and control the styles of various elements in HTML. We can write CSS code in thec9ccee2e6ea535a969eb3f532ad9fe89tag in the head of the HTML document, or we can write the style code into an external CSS file. In the above code, we have used internal styles to define the font color of the h1 element.

2. Basic knowledge of click events

Click events are one of the most commonly used interaction methods in JavaScript. When a user clicks on an element on a web page, the element will trigger a "click event", and then we can process the element by writing JavaScript code. The following is a simple sample code:

      
  
点击我改变颜色
  

In the above code, we first add acursor: pointerstyle to the h1 element, so that when the mouse is hovering over the h1 element It will turn into a hand shape, prompting the user to click on the element. Subsequently, a function namedchangeColor()was written in the3f1c4e4b6b16bbbd69b2ee476dc4f83atag. The function of this function is to change the font color of the h1 element to blue. Finally, theonclickattribute is added to the4a249f0d628e2318394fd9b75b4636b1tag. The value of this attribute is thechangeColor()function we just defined, so click on the h1 element When thechangeColor()function is triggered, the function of changing the color is realized.

3. Change CSS through click events

Through the above sample code, we can see that HTML elements can be operated through JavaScript click events, such as changing styles. Here is another example code for changing CSS through click events:

      
  
点击变蓝
 
点击变红
  

In the above code, we first define two styles, one is the initial style of the h1 element, and the other is when the h1 element is clicked The style after, where.changeColoris a class selector used to add and remove styles of h1 elements. Subsequently, we defined two functionsaddClass()andremoveClass(), which are used to add and delete the styles of h1 elements respectively. In the6c04bd5ca3fcae76e30b72ad730ca86dtag, we added two h1 elements respectively, and boundaddClass()andremoveClass to theonclickattribute ()function realizes the effect of clicking to change the style of h1 element.

Summary:

Through the above example code, we can learn how to change CSS through click events to achieve interactive effects on web pages. Of course, this is just a basic operation. In fact, more complex interactive effects can be achieved through JavaScript. Therefore, we need to continue to learn and master more JavaScript skills and knowledge in order to better achieve web page interaction effects.

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