What is the javascript delete button function?

With the continuous improvement of Javascript technology, we can develop various practical functions to solve problems in daily work. Among them, the delete button function is a very practical one, which can help us easily delete specified content on the web page. Next, let us learn the creation process of Javascript delete button function.

First of all, before creating the Javascript delete button function, we need to master some basic knowledge. First, we need to know how to get an element from a web page in Javascript so that we can modify its content if needed. Secondly, we need to master how to use loops and conditional statements in Javascript to operate on multiple elements in the web page. Finally, we need to learn how to use event handlers in Javascript to trigger the delete action when the user clicks the button.

Next, we can create the simplest Javascript delete button function, which can help us delete any element on the web page. The specific code is as follows:

function deleteElement(elementID) {
  var element = document.getElementById(elementID);
  element.parentNode.removeChild(element);
}

In this function, we first use the document.getElementById() method to obtain the element that needs to be deleted, and then use the parentNode.removeChild() method to delete it from the web page. The parameter of this function is the ID number of the element that needs to be deleted, which is the element identifier we defined in the web page.

However, this function still has many shortcomings. For example, it can only delete one element in a web page, but cannot achieve batch deletion. Next, let’s explore how to create a Javascript function that can delete elements in batches.

First, we need to create a set of elements that need to be deleted in the web page and define a unique ID number for each element. Next, let's take a look at the sample code:

<ul>
  <li id="item1">列表项1</li>
  <li id="item2">列表项2</li>
  <li id="item3">列表项3</li>
</ul>
<button onclick="deleteElements()">删除选定项</button>

In this code, we create a list that contains three list items, each list item has a unique ID number. Additionally, we created a button and bound it to a new function deleteElements(). Next, let's take a look at how to write this function.

function deleteElements() {
  var ul = document.querySelector('ul');
  var items = ul.querySelectorAll('li:checked');
  
  for(var i = 0; i < items.length; i++) {
    ul.removeChild(items[i]);
  }
}

In this function, we first use the querySelector() method to obtain the list element ul. Next, we use the querySelectorAll() method to obtain all selected list items and save them in the variable items. Next, we use a for loop to iterate through all selected list items and remove them from the web page using the removeChild() method.

In this function, we use some relatively new Javascript syntax, such as the querySelector() and querySelectorAll() methods, the let keyword in the for loop, etc. These syntaxes make it easier for us to write complex Javascript functions and improve code readability and performance.

In short, the Javascript delete button function is a very practical function that can help us delete content on the web page conveniently and quickly. Through the above introduction, I believe you have learned how to create a simple Javascript deletion function and how to extend it to implement batch deletion. In daily development, we can further optimize these functions according to specific needs and create more efficient and practical Javascript tools.

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