js code for selecting table rows using the up and down keys on the keyboard_javascript skills

//This is the form to be operated on: <table id="tb"> <tr> <td>这是第一行</td> </tr> <tr> <td>这是第二行</td> </tr> <tr><td>这是第三行</td></tr> <tr><td>这是第四行</td></tr> </table> //This is the code to operate the table <input type="text" id="show" value="do">
[Ctrl A select all Note: If you need to introduce external Js, you need to refresh to execute

]<script> var rowNo= -1; var tableId = 'tb'; var inputId = 'show'; var selectedColor = "#FF0000" function document.onkeydown() { //事件的标识代码 if (event.keyCode == 38) { for(var k=0;k<document.getElementById(tableId).rows.length;k++) { document.getElementById(tableId).rows(k).bgColor="#FFFFFF"; } if(rowNo == 0) { rowNo++; } document.getElementById(tableId).rows(--rowNo%document.getElementById(tableId).rows.length).bgColor=selectedColor; document.getElementById(inputId).value=document.getElementById(tableId).rows(rowNo%document.getElementById(tableId).rows.length).innerText; } //事件的标识代码 if (event.keyCode== 40) { for(var k=0;k<document.getElementById(tableId).rows.length;k++) { document.getElementById(tableId).rows(k).bgColor="#FFFFFF"; } document.getElementById(tableId).rows(++rowNo%document.getElementById(tableId).rows.length).bgColor=selectedColor; document.getElementById(inputId).value=document.getElementById(tableId).rows(rowNo%document.getElementById(tableId).rows.length).innerText; } } </script>