CareerCup

Basically, keep track of the number of columns for each row in some list structure, then sort the list and grab the highest value.

For each row (<TR>) count the header and detail elements (<TH> and <TR>); for each one, increment the corresponding entry in your list structure. The trick is to look for ROWSPAN attributes within the TH and TD elements; if you find such a rowspan attribute, increment the appropriate number of subsequent entries in your list structure, as well.

Semi-Pseudo code:

ArrayList<int> columnCounter = new ArrayList<int>();
int rowIndex = 0;
find the start of the table;
For each "<TR " or "<TR>" {
    For each "<TH ", "<TH>", "<TD " or "<TD>" after the closing ">" of the TR {
        if (rowIndex + 1 > columnCounter.size())
            columnCounter.add(0);
        columnCounter[rowIndex]++;
        if ROWSPAN before the closing ">" of the TH or TD and if ROWSPAN > 1 {
            for (int i = 1; i < ROWSPAN Value; i++) {
                if (rowIndex + i + 1 > columnCounter.size())
                    columnCounter.add(0);
                columnCounter[rowIndex + i]++;
            }
        }
    }
    rowIndex++;
}

columnCounter.sort();
if !columnCounter.isEmpty()
  return columnCounter[columnCounter.size() - 1];
return 0;

When finding the TR, TH, TD and ROWSPAN strings, be sure to ignore commented or quoted instances

Using Jquery:
alert(numCol("table") + " is the max number of cols");
function numCol(table) {
var maxColNum = 0;
var i=0;
var trs = $(table).find("tr");

// var thead = $(table).find("tr").find("th");
for ( i=0; i<trs.length; i++ ) {
var span = $(trs[i]).attr("colspan");
var thead= $(trs[i]).find("th");

if (thead)
{
if(span){

maxColNum += parseInt(span);
}
maxColNum++;
}
else {
maxColNum++;
}
}
return maxColNum;
}