javastrip trim()——字符串方法

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA_Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Title</title>
    <link rel="stylesheet" href="bootstrap-3.3.7-dist/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<input type="text"> <button>点击</button>
<div></div>
<script>
    // trim 方法去除字符串两侧空格
    // trim()方法会从一个字符串的两端删除空白字符。
    // str.trim()
    // trim)方法并不影响原字符串本身,它返回的是一个新的字符串。
    var str = '    an  dy    ';
    console.log(str);//'    an  dy    '
    var str1 = str.trim();
    console.log(str1);// 'an  dy'
    console.log('++++++++++++++++++++++++++++++++++++++++++++++++');//分割线,下面是练习用法
    var input = document.querySelector('input');
    var btn = document.querySelector('button');
    var div = document.querySelector('div');
    btn.addEventListener('click',function () {
        var str = (input.value).trim();
        if(str === ""){
            alert("请输入内容");
        } else{
            div.innerHTML = str;
        }
    })
</script>
</body>
</html>

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转载自blog.csdn.net/weixin_45949073/article/details/107444163