1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="utf-8"> 5 <meta http-equiv="X-UA-Compatible" content="IE=edge"> 6 <title></title> 7 <link rel="stylesheet" href=""> 8 </head> 9 <body> 10 <form action=""> 11 <p> 12 <label for="backgroundColor">选择背景色:</label> 13 <select id="backgroundColor"> 14 <option value="white" selected="selected">White</option> 15 <option value="black">Black</option> 16 </select> 17 </p> 26 27 <p> 28 <input type="button" id="previewButton" value="Preview"> 29 </p> 30 </form> 31 32 <script> 33 var bgColor = document.getElementById('backgroundColor'); 34 var preview = document.getElementById('previewButton'); 35 36 var index = bgColor.selectedIndex; 37 var value = bgColor[index].value; 38 39 preview.addEventListener('click',function(){ 40 console.log(index); //0 41 console.log(value); //white 42 }) 43 44 </script> 45 </body> 46 </html>