jquery determines whether data is repeated

In web development, it is often necessary to determine whether the specified data already exists. Especially during operations such as form submission, the uniqueness of the data needs to be ensured. You can use jQuery to easily determine whether data is duplicated. This article will introduce in detail how to use jQuery to implement the data duplication determination function.

1. What is jQuery?

First of all, we need to understand what jQuery is. jQuery is an excellent JavaScript library that simplifies the writing of JavaScript and provides a simple and easy-to-use API that can easily handle document traversal, event processing, animation effects, AJAX and other operations. Using jQuery can save a lot of development time and improve the development efficiency of WEB applications.

2. Two methods to determine whether data is duplicated

When using jQuery to determine whether data is duplicated, there are generally two methods:

1. Use jQuery's is () method to determine whether data exists in the selector;

2. Store the data in an array and use jQuery's inArray() method to determine whether the data already exists.

The implementation of these two methods is introduced in detail below.

3. Use jQuery's is() method to determine whether the selector has data.

Use jQuery's is() method to determine whether the selector has data. If data exists, it will return true. Otherwise return false. Using this method requires processing the selector, replacing the data in the selector with the data to be judged, and then using the is() method to judge. The following is a simple example:

//判断输入的是否是数字
$('input').blur(function(){
    var value = $(this).val(); //获取输入框的值
    if( !isNaN(value) && value !== ''){
        var isExist = $('td:contains('+ value +')').is(function(){
            return $(this).text() === value;
        }); //使用is()方法判断是否存在数字
        if(isExist){
            alert('数据已经存在'); //数据已经存在
            return false;
        }else{
            //保存数据
        }
    }
});

In the above code, first get the value of the input box, and then use the is() method to determine whether the same data exists. Here, we use the selector td:contains to locate cells that contain the same data, and use the function return value to determine whether the data already exists. If the same data exists, a prompt box will pop up, otherwise the data will be saved.

4. Store the data in an array and use jQuery’s inArray() method to determine whether the data already exists.

Another way to determine whether the data is repeated is to store the data in an array. Use jQuery's inArray() method to determine whether the data already exists in the array. In this case, we need to create an array to store the data, and then use the inArray() method to determine whether the data already exists. The following is a simple example:

//判断输入的是否是数字
$('input').blur(function(){
   var value = $(this).val(); //获取输入框的值
   if( !isNaN(value) && value !== ''){
       var dataArray = []; //定义一个数组来存储数据
       $('td').each(function(){
           dataArray.push($(this).text()); //将数据添加到数组中
       });
       if($.inArray(value, dataArray) !== -1){
           alert('数据已经存在'); //数据已经存在
           return false;
       }else{
           //保存数据
       }
   }
});

In the above code, we define an array dataArray to store data, and then use the each() method to traverse all cells and add data to the array. Finally, use the inArray() method to determine whether the input data already exists in the array. If it exists, a prompt box will pop up, otherwise the data will be saved.

5. Summary

Using jQuery can easily judge duplicate data. We can choose a more suitable method to judge according to the specific situation. The above two methods are simple and easy to use, which can save developers a lot of development time and improve development efficiency. At the same time, this also reflects the simplicity, ease of use and powerful functions of jQuery, providing a more convenient tool for WEB development.

The above is the detailed content of jquery determines whether data is repeated. For more information, please follow other related articles on the PHP Chinese website!