监听键盘上下键 | 易学教程

  <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">  
    <html>  
      <head>      
        <title>keyboard control 1</title>      
        <style>  
            tr.highlight{background:#08246B;color:white;}  
        </style>  
      </head>    
      <body>  
    <table border="1" width="70%" id="ice">  
        <tr>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
        </tr>  
        <tr>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
        </tr>  
        <tr>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
        </tr>  
        <tr>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
        </tr>  
        <tr>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
            <td><input type='text'></td>  
        </tr>  
    </table>  
    <script language="javascript">  
    <!--  
    //定义初始化行列  
    var currentLine=0;  // 目前的行号  
    var currentCol=0;  
     var objtab=document.all.ice;  
     var colums = objtab.rows[4].cells.length;  
    var objrow=objtab.rows[0].getElementsByTagName("INPUT");  
     objrow[0].select();  
    document.body.onkeydown=function(e){  
      e=window.event||e;  
      switch(e.keyCode){  
        case 37: //左键  
          currentCol--;  
          changeItem(e);  
          break;  
        case 38: //向上键  
          currentLine--;  
          changeItem(e);  
          break;  
        case 39: //右键  
          currentCol++;  
          changeItem(e);  
          break;  
        case 40: //向下键  
          currentLine++;  
          changeItem(e);  
          break;  
        default:  
          break;  
      }  
    }  
    //方向键调用  
    function changeItem(e){  
      if(document.all){//如果是IE  
        var it=document.getElementById("ice").children[0];   //获取table表单元素  
      }else{//其他浏览器  
        var it=document.getElementById("ice");  
      }  
         
     if(e.keyCode==37||e.keyCode==39){  
        if(currentLine<0){//如果行小于0  
            currentLine=it.rows.length-1;  
          }  
          if(currentLine==it.rows.length){  
           currentLine=0;  
          }  
          var objtab=document.all.ice;  
          var objrow=objtab.rows[currentLine].getElementsByTagName("INPUT");  
            
           
          if(currentCol<0){  
             
            if(e.keyCode==37){  
                currentLine--;  
                if(currentLine<0){//如果行小于0  
                    currentLine=it.rows.length-1;  
                 }  
                objrow=objtab.rows[currentLine].getElementsByTagName("INPUT");    
            }  
            currentCol=objrow.length-1;  
          }  
            
          if(currentCol>=objrow.length){  
            if(e.keyCode==39){  
                currentLine++;  
                 if(currentLine==it.rows.length){  
                  currentLine=0;  
                  }   
                  objrow=objtab.rows[currentLine].getElementsByTagName("INPUT");      
            }  
            currentCol=0;    
              
          }    
     }else{  
        if(currentLine<0){//如果行小于0  
            currentLine=it.rows.length-1;  
            currentCol--;  
            if(currentCol<0){  
                currentCol=colums-1;  
            }  
          }  
          if(currentLine==it.rows.length){  
             currentLine=0;  
             currentCol++;  
             if(currentCol>=colums){  
                currentCol=0;  
             }  
          }  
          var objtab=document.all.ice;  
          var objrow=objtab.rows[currentLine].getElementsByTagName("INPUT");  
          while(e.keyCode==40&&objrow[currentCol]==undefined){  
            currentLine++;  
            objrow=objtab.rows[currentLine].getElementsByTagName("INPUT");        
          }  
          while(e.keyCode==38&&objrow[currentCol]==undefined){  
            currentLine--;        
            objrow=objtab.rows[currentLine].getElementsByTagName("INPUT");    
          }  
            
     }    
      objrow[currentCol].select();  
    }  
    //-->  
    </script>  
      </body>  
    </html>
来源：CSDN
作者：柠檬草。
链接：https://blog.csdn.net/yyx3214/article/details/103973541
标签
input
keycode
getelementsbytagname