Adding table rows and columns in JavaScript

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With insertRow() method you can insert a new row at the specified position in HTML table. After row is created, use insertCell() method to insert a table cell. Wrap this methods in JavaScript functions and you have code to dynamically add new rows and columns in the HTML table. Please try to click the buttons below ...



Small
HTML
table

When you click the "Add row" button, appendRow() function is called. Function is simple, table row is inserted at the last position, and loop iterates through table cells in the first row. Why first row? Because you have to know the number of columns. For each step (cell in the first row), createCell() function creates and attaches DIV element to the newly created table cell.

// append row to the HTML table
function appendRow() {
    var tbl = document.getElementById('my_table'), // table reference
        row = tbl.insertRow(tbl.rows.length),      // append table row
        i;
    // insert table cells to the new row
    for (i = 0; i < tbl.rows[0].cells.length; i++) {
        createCell(row.insertCell(i), i, 'row');
    }
}

// create DIV element and append to the table cell
function createCell(cell, text, style) {
    var div = document.createElement('div'), // create DIV element
        txt = document.createTextNode(text); // create text node
    div.appendChild(txt);                    // append text node to the DIV
    div.setAttribute('class', style);        // set DIV class attribute
    div.setAttribute('className', style);    // set DIV class attribute for IE (?!)
    cell.appendChild(div);                   // append DIV to the table cell
}

createCell() also sets class attribute (needed for the red and green background color) to the DIV element. It' not necessary to create DIV element (you can append only text node to the TD element), but this is a good example of how to create and append new element to the table cell. appendColumn() is similar to the appendRow() function. For each table row, new cell is inserted to the last position in the row.

// append column to the HTML table
function appendColumn() {
    var tbl = document.getElementById('my_table'), // table reference
        i;
    // open loop for each row and append cell
    for (i = 0; i < tbl.rows.length; i++) {
        createCell(tbl.rows[i].insertCell(tbl.rows[i].cells.length), i, 'col');
    }
}

Here is code used to delete table rows and columns ("Delete both" button, calls both functions).

// delete table rows with index greater then 0
function deleteRows() {
    var tbl = document.getElementById('my_table'), // table reference
        lastRow = tbl.rows.length - 1,             // set the last row index
        i;
    // delete rows with index greater then 0
    for (i = lastRow; i > 0; i--) {
        tbl.deleteRow(i);
    }
}

// delete table columns with index greater then 0
function deleteColumns() {
    var tbl = document.getElementById('my_table'), // table reference
        lastCol = tbl.rows[0].cells.length - 1,    // set the last column index
        i, j;
    // delete cells with index greater then 0 (for each row)
    for (i = 0; i < tbl.rows.length; i++) {
        for (j = lastCol; j > 0; j--) {
            tbl.rows[i].deleteCell(j);
        }
    }
}

This entry was posted on May 8, 2009 and is filed under JavaScript

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67 Responses to Adding table rows and columns in JavaScript

  1. RazieL says:

    Hi. How can i give every cell an ID like in excel table. For every row to give numbers 1, 2,3 etc. and for every column to give letters a, b, c etc.
    So in the end it must look like a1, b3, d1, d2 etc.

    Thanks

  2. dbunic says:

    @RazieL - As you can see, JavaScript functions are very simple and with some additional logic you can assign id to every table cell. Try to extend createCell() method with the following line at the end:

    cell.setAttribute('id', 'a1');
    

    This should assign "a1" to every cell in table. Instead of string "a1" you can place variable and define unique id. Hope this will point you to the right direction.

  3. ilias says:

    Hi! If you have an unknown number of parameters that you want to post, you can declare the name on the following way:

    cell.setAttribute('name', 'a1[]');
    
  4. dbunic says:

    @ilias - You are right. When form with such named parameter is submitted, parameter will be accepted as an array (on the PHP side) ... and thank you for posting a comment.

  5. Christy Matthewson says:

    Thank you for this!

  6. dbunic says:

    @Christy - This is small code but it can be a good start point for further development. I'm glad it was useful.
    Cheers!

  7. Raju says:

    Hi Dbunic,
    I have a html table and insert a new row with table.insertRow(), but the new row doesn't have any attributes or formatting applied. How can I add a row to the table with attr ( id , title,)?

    Looking for ur support

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