How to edit javascript in table

Table is one of the commonly used elements in WEB development, used to display data or layout pages, etc. Table-related JavaScript operations are also one of the necessary skills for developers. This article will introduce in detail how to edit the JavaScript operation of the table.

1. Basic knowledge of tables

In HTML, tables are implemented using tags such as table, tr, th, td, etc., where table represents the entire table, tr represents the rows in the table, and th represents the table. The header cell in , td represents the data cell in the table. The following is a simple table:

<table>
  <tr>
    <th>姓名</th>
    <th>年龄</th>
    <th>性别</th>
  </tr>
  <tr>
    <td>Tom</td>
    <td>20</td>
    <td>男</td>
  </tr>
  <tr>
    <td>Mary</td>
    <td>25</td>
    <td>女</td>
  </tr>
</table>

In this way, a table containing three columns of data can be displayed on the page. Next, we will use this table as an example to show how to edit the table through JavaScript.

2. Get the table object

In JavaScript, we can get the table object through the getElementById method or getElementsByTagName method of the document object, for example:

var table = document.getElementById("tableId"); //通过id获取表格对象
var td = document.getElementsByTagName("td"); //通过标签名获取所有表格单元格对象

Use the getElementById method to get the table The object needs to add the id attribute to the corresponding table in HTML, for example:

<table id="tableId">
  <!-- 表格内容 -->
</table>

3. Get the rows and cells in the table

Getting the rows and cells in the table is the most effective way to operate the table. One of the basic operations. We can get all the rows of the table through the rows attribute of the table object, and get all the cells in the row through the cells attribute of the row object. For example:

//获取表头行对象
var thead = table.rows[0];
//获取第一行对象
var tr = table.rows[1];
//获取第一行第一列单元格对象
var td = table.rows[1].cells[0];
//获取第二行第三列单元格对象
var td2 = table.rows[2].cells[2];

4. Add rows and cells

It is often necessary to dynamically add rows and cells in tables. We can add rows through the insertRow method, which returns a row object, and we can add cells through the object's insertCell method. For example:

//在表格第二个位置插入一行
var newRow = table.insertRow(1);
//在该行第一个位置插入一个单元格
var newCell = newRow.insertCell(0);
newCell.innerHTML = 'Jerry';
//在该行第二个位置插入一个单元格
newCell = newRow.insertCell(1);
newCell.innerHTML = 18;
//在该行第三个位置插入一个单元格
newCell = newRow.insertCell(2);
newCell.innerHTML = '男';

In this way, a row is inserted at the second position of the table, and three cells are inserted into the row.

5. Deleting rows and cells

Deleting rows and cells in a table is also a common operation. We can delete rows through the remove method of the row object, or delete cells through the remove method of the cell object. For example:

//获取第三行对象
var row = table.rows[2];
//删除该行
table.deleteRow(row.rowIndex);
//获取第一行第二个单元格对象
var cell = table.rows[0].cells[1];
//删除该单元格
cell.parentNode.removeChild(cell);

6. Merge cells

Sometimes we need to merge adjacent cells in the table to lay out the page or display data, etc. We can use the rowSpan and colSpan properties to merge cells. For example:

//合并第一行第一列和第二列单元格
var td1 = table.rows[0].cells[0];
td1.rowSpan = 2;
//删除第二行第一列单元格
table.rows[1].deleteCell(0);

This merges the cells in the first row, first column and second column, and deletes the cells in the second row, first column.

7. Modify cell content

In addition to adding, deleting, and merging cells, modifying cell content is also one of the common operations. We can modify the text content inside the cell through the innerHTML property or innerText property of the cell object. For example:

//获取第二行第三列单元格对象
var td = table.rows[2].cells[2];
//修改单元格内部文本内容
td.innerHTML = '女';

At this time, the cell text content in the second row and third column will change to "Female".

8. Summary

The above introduces the common operations of JavaScript editing of tables, including obtaining table objects, obtaining rows and cells, adding and deleting rows and cells, merging cells, and modifying cells. Grid content, etc. Mastering these operations can bring more convenience and flexibility to our table editing, and can also improve our WEB development capabilities.

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