var str = ' hello ' console.log(str.trim()) //hello 去除两端空格 var str1 = ' he l l o ' console.log(str.trim()) //he l l o 去除两端空格
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> </head> <body> <input type="text"> <button>点击</button> <div></div> <script> // trim 方法去除字符串两侧空格 var str = ' an dy '; console.log(str); var str1 = str.trim(); console.log(str1); var input = document.querySelector('input'); var btn = document.querySelector('button'); var div = document.querySelector('div'); btn.onclick = function() { var str = input.value.trim(); if (str === '') { alert('请输入内容'); } else { console.log(str); console.log(str.length); div.innerHTML = str; } } </script> </body> </html>