Use jQuery to read text files and process them line by line

This article demonstrates how to use the AJAX $.get() method built in jQuery to read text files and process file content line by line. The sample code adds the file content line by line to the HTML element and displays it on the page. Note that this jQuery code will only replace the first appearance of the word "jQuery4u" and will not replace all appearances like PHP's str_replace(). To replace all occurrences of strings in JavaScript, the replace() method must be provided with a regular expression with a global modifier as the first parameter, for example: .replace(/jQuery4u/g,'jQuery4u FTW!');

jQuery code: read text file line by line

jQuery.get('file.txt', function(data) {
   //alert(data); //可選：顯示完整文件內(nèi)容
   //逐行處理文本文件
   let lines = data.split('\n'); // 使用 \n 分隔符
   let output = '';
   $.each(lines, function(index, line) {
       output += line + '<br>'; // 添加換行符以便在頁面上顯示
   });
   $('#div').html(output); // 將處理后的內(nèi)容添加到id為div的元素中
});

Important Security Tips: For security reasons, the browser restricts access to local drives (and server drives). However, you can use the standard jQuery ajax call $.ajax().

FAQs (FAQs)

How to use jQuery to read local text files?

You can use jQuery's $.get() method to read local text files. This method uses HTTP GET requests to load data from the server. Here is a simple example:

$.get("file.txt", function(data) {
  alert("已加載數(shù)據(jù): " + data);
});

In this example, "file.txt" is the local text file to be read. function(data) is a callback function that is executed if the request is successful. The data parameter contains the data returned from the server - in this case, the contents of the text file. Please note that directly reading local files often fails due to browser security restrictions. This method is more suitable for reading files from the server.

Can I use jQuery to read text files in different fields?

Due to the security restrictions of the same-origin policy, it is impossible to use jQuery's AJAX method to read text files in different domains. Same-origin policies limit how documents or scripts loaded from one source interact with resources from another source. However, there are ways to circumvent this limitation, such as using server-side proxy or JSONP, but these methods have their own limitations and security issues.

How to deal with errors when reading text files using jQuery?

The errors when using jQuery to read text files can be handled using the .fail() method. This method is called when the request fails. Here is an example:

$.get("file.txt")
.done(function(data) {
  alert("已加載數(shù)據(jù): " + data);
})
.fail(function() {
  alert("發(fā)生錯誤");
});

In this example, if the request to load "file.txt" fails, the .fail() method is called and an error message is displayed.

Can I use jQuery to read text files line by line?

jQuery does not provide a built-in method to read text files line by line. However, this can be achieved by splitting the file contents by line breaks. Here is an example:

$.get("file.txt", function(data) {
  var lines = data.split("\n");
  $.each(lines, function(index, line) {
    console.log("第 " + (index+1) + " 行: " + line);
  });
});

In this example, the file content is divided into an array of lines by a newline character ("n"). Then, each line is recorded in the console.

How to use jQuery to read CSV files?

The method of using jQuery to read CSV files is similar to reading text files. However, the file content needs to be parsed into available formats. Here is an example:

jQuery.get('file.txt', function(data) {
   //alert(data); //可選：顯示完整文件內(nèi)容
   //逐行處理文本文件
   let lines = data.split('\n'); // 使用 \n 分隔符
   let output = '';
   $.each(lines, function(index, line) {
       output += line + '<br>'; // 添加換行符以便在頁面上顯示
   });
   $('#div').html(output); // 將處理后的內(nèi)容添加到id為div的元素中
});

In this example, each line of the file is divided into an array of fields by a comma character (","). Each field array is then recorded to the console.

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