使用.input-sm类在Bootstrap中设置小输入字段。
您可以尝试运行以下代码来实现.input-sm类：
<!DOCTYPE html> <html lang="en"> <head> <title>Bootstrap Example</title> <meta charset = "utf-8"> <meta name = "viewport" content = "width=device-width, initial-scale = 1"> <link rel = "stylesheet" href = "https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css"> <script src = "https://cdn.staticfile.org/jquery/3.3.1/jquery.min.js"></script> <script src = "https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script> </head> <body> <div class = "container"> <h2>Candidate Profile</h2> <form> <div class="form-group"> <label for="sel2">What is your job profile?</label> <select class="form-control input-lg" id="sel2"> <option>Programmer</option> <option>Web Developer</option> <option>DBA</option> <option>Support Engineer</option> </select> </div> <div class="form-group"> <label for="sel3">Educational Qualification</label> <select class="form-control input-sm" id="sel3"> <option>Undergraduate</option> <option>Graduate</option> <option>Post-Graduate</option> </select> </div> </form> </div> </body> </html>