javascript delete by line

JavaScript is a programming language widely used in front-end development, which can achieve page interaction and dynamic effects very well. When implementing some specific functions, we will encounter the problem of deleting rows. This article will introduce how to implement line-by-line deletion in JavaScript.

1. Get the text content

First, we need to get the text content to be operated. In JavaScript, you can use textarea, input and other tags to obtain text input. Here, we use the textarea tag as an example:

<textarea id="text"></textarea>

The content of the text box can be obtained through the id attribute of the tag:

var text = document.getElementById("text").value;

2. Split the text

Next, we The text content needs to be split by lines, and the split() function is used here.

var lines = text.split('
');

In this example, we use the newline character "
" as the delimiter, that is, the text content is separated into multiple lines according to the newline character and stored in an array called lines. .

3. Delete specific rows

Next, we can operate on the rows that need to be deleted. For example, now we want to delete the content of line 3, we can use the splice() function.

lines.splice(2,1);

In this example, the first parameter "2" in the splice() function represents the number of rows to be deleted, and the second parameter "1" represents the number of rows to be deleted. In this way, the content of line 3 is deleted.

4. Combining text

Finally, we need to recombine the modified text, that is, splicing each line of text in the array into a complete string.

var newText = lines.join("
");

In this example, the join() function is used to recombine all the lines in the lines array into a string, and the newline character "
" is used as the separator.

5. Replace the original content

Finally, we will replace the modified text into the original text box.

document.getElementById("text").value = newText;

In this way, we have implemented the operation of deleting text by line.

The complete code is as follows:

<textarea id="text"></textarea>
删除第三行
<script>
function deleteLine() {
    var text = document.getElementById(&quot;text&quot;).value;
    var lines = text.split('
');
    lines.splice(2,1);
    var newText = lines.join(&quot;
&quot;);
    document.getElementById(&quot;text&quot;).value = newText;
}
</script>

The above is the method of using JavaScript to delete text by line. Please note that this method only works for text delimited by the newline character "
". If other delimiters are used, you need to make corresponding modifications.

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