JavaScript is a scripting language widely used in web development. In the actual development process, we often encounter situations where data display is required. When displaying data, sometimes it is necessary to convert line breaks in the data into HTML <br> tags. In this article, we will introduce how JavaScript performs line break conversion.
1. What is a newline character<br>In JavaScript, the most common newline character is `<br>. In fact, in operating systems, different systems use different line breaks. For example, in Windows systems, the newline character is <br>, while in Unix or Linux systems, the newline character is <br>`. Because of this variability, errors can occur if they are not considered clearly during development.
2. How to convert newlines in JavaScript<br>In JavaScript, you can use regular expressions to replace newlines. The following is a simple function example:
function formatString(str) {
if(!str) return str;
return str.replace(/
/g, "<br>");
}In the above function, the regular expression `<br> is used to match the newline character, and the replace method is used to replace it with the HTML tag <br>. Among them, /g` represents global matching. In this way, when calling the function, you only need to pass in the string to be converted to newline. The example is as follows:
var str = "这是第一行 这是第二行 这是第三行"; var formattedStr = formatString(str); console.log(formattedStr);
After executing the above code, the console output should be:
这是第一行<br>这是第二行<br>这是第三行
3. Usage example<br> If you need to display the input in a multi-line text box on the web page content, you need to convert line breaks. The following is a simple web page example:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>javascript line break to br</title>
<style>
#content {
width: 400px;
height: 200px;
border: 1px solid #ccc;
}
</style>
</head>
<body>
<h1 id="javascript-line-break-to-br">javascript line break to br</h1>
<div>
<textarea id="content"></textarea>
</div>
<input type="button" value="提交" onclick="submitContent()">
<script>
function formatString(str) {
if(!str) return str;
return str.replace(/
/g, "<br>");
}
function submitContent() {
var content = document.getElementById("content").value;
var formattedContent = formatString(content);
console.log(formattedContent);
}
</script>
</body>
</html>In the above web page, we use a text box and a submit button. When the user enters content in the text box and clicks the submit button, the converted content. The effect is as shown in the figure below:
IV. Notes<br> When converting line breaks, you need to pay attention to the following matters:
- is different Differences in newline characters in the system;
- in regular expressions `<br>
represents newline characters, not<br>`; - requires global matching when replacing , and use the HTML
<br>tag instead of `<br>`.
5. Summary<br>In JavaScript, line break conversion is sometimes necessary. By using regular expressions and string replacement methods, you can quickly convert newlines to <br> tags. In order to avoid errors caused by system newline character differences, you should try to use `<br>` as the matching symbol for newline characters.
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