Hiding columns in table JavaScript

Question

This script stops working the moment I add a table inside a table, so how to get it worked? I don\'t need any jQuery solutions, I want pure JavaScript. Here\'s my sc

Answer 1

You could use children and check their tagName to make sure they're td's. Something like this:

function show_hide_column(col_no, do_show) {
    var tbl = document.getElementById('id_of_table');
    var rows = tbl.getElementsByTagName('tr');

    for (var row = 0; row < rows.length; row++) {
        var cols = rows[row].children;
        if (col_no >= 0 && col_no < cols.length) {
            var cell = cols[col_no];
            if (cell.tagName == 'TD') cell.style.display = do_show ? 'block' : 'none';
        }
    }
}

Edit: Here's a working example: http://jsfiddle.net/3DjhL/2/.

Edit: In fact, I've just remembered the rows and cols properties, which make it even simpler. See http://jsfiddle.net/3DjhL/4/ to see it in action.

function show_hide_column(col_no, do_show) {
    var rows = document.getElementById('id_of_table').rows;

    for (var row = 0; row < rows.length; row++) {
        var cols = rows[row].cells;
        if (col_no >= 0 && col_no < cols.length) {
            cols[col_no].style.display = do_show ? '' : 'none';
        }
    }
}

Oh, and if you think the column numbers should start at 1 (which they don't), you'll have to offset that somewhere. For example at the top of show_hide_column():

col_no = col_no - 1;

Answer 2

If you can leverage the col tag the solution, in pure JavaScript, is straightforward:

<table id='id_of_table' border=1>
  <col class="col1"/>
  <col class="col2"/>
  <col class="col3"/>
  <col class="col4"/>
  <tr><td colspan="4"><table><tr><td></td></tr></table></td></tr>
  <tr><td>  2</td><td>   two</td><td>   deux</td><td>     zwei</td></tr>
  <tr><td>  3</td><td> three</td><td>  trois</td><td>     drei</td></tr>
  <tr><td>  4</td><td>  four</td><td>quattre</td><td>     vier</td></tr>
  <tr><td>  5</td><td>  five</td><td>   cinq</td><td>fÜnf</td></tr>
  <tr><td>  6</td><td>   six</td><td>    six</td><td>    sechs</td></tr>
</table>

You can apply to col just a couple of CSS attributes, but visibility is one of them:

function show_hide_column(col_no, do_show) {
   var tbl = document.getElementById('id_of_table');
   var col = tbl.getElementsByTagName('col')[col_no];
   if (col) {
     col.style.visibility=do_show?"":"collapse";
   }
}

References:

• col
• visibility on quirksmode

Answer 3

I had a situation where it would have been a very big hassle to modify every single TD value and add the appropriate class name so I could toggle it. As a result I wrote some JavaScript to do that automatically. Please see the following code.

  tbl = document.getElementById("Mytable")
  classes = getClasses(tbl.rows[0]);
  setClasses(tbl, classes);
  toggleCol("col0");
  toggleCol("col1");



function getClasses(row){
    var cn = 0;
    var classes = new Array();
    for(x=0; x < row.cells.length; x++){
        var cell = row.cells[x];
        var c = new Column(cell.textContent.trim(), cell.offsetLeft, cell.offsetLeft + cell.offsetWidth, x);
        classes[x]= c;
    }
    return classes;
}

function Column(name, left, right, cols) {
    this.name = name;
    this.left = left;
    this.right = right;
    this.cols = cols;
}

function setClasses(table, classes){
    var rowSpans = new Array();
    for(x=0; x < table.rows.length; x++){
        var row = table.rows[x]; 
        for(y=0; y < row.cells.length; y++){
            var cell = row.cells[y];
            for(z=0; z < classes.length; z++){
              if(cell.offsetLeft >= classes[z].left && cell.offsetLeft <= classes[z].right){
                cell.className = "col" + classes[z].cols;
              }
            }
        }    
    }
}

function toggleCol(name){ 
  var cols = document.getElementsByClassName(name); 
  for(x=0; x < cols.length; x++){ 
    cols[x].style.display= (cols[x].style.display == 'none') ? '' : 'none'; 
   }
}

In my example I take a look at the first row to set the top level header (In my example I had several who had colspans). It uses the offsetLeft and offsetWidth to determine the range of the top header (which in my cases has sub headers), so that all sub-columns would toggle with its parent.

Based on these values setClasses sets the appropriate classes to all the elements.

In my example I then toggle "col0" and "col1", so they would be invisible (Running the function again would make them visible again).