如何用javascript检查给定html表有多少列？

function calculateCells(){
    var table = document.getElementById(\"table\");
    var max = 0;
    for(var i=0;i<table.rows.length;i++) {
        if(max < table.rows[i].cells.length)
            max = table.rows[i].cells.length;
    }
    return max;
}

<tr>

<tr>

<td>

<td>

var table = document.getElementById(\"myTable\");
var max = 0;

for (var i = 0, iLen = table.rows.length; i < iLen; i++) {
  var temp = 0;
  var cells = table.rows[i].cells;

  for (var j = 0, jLen = cells.length; j < jLen; j++) {
    // This is very important. If you just take length you\'ll get the
    // the wrong answer when colspan exists
    temp += cells[j].colSpan;
  }

  if (temp > max) {
    max = temp;
  }
}

alert(max);

max

var max = 0;
$(\"tr\").each(function() {
   var count = $(this).find(\"td\").length;
    if(count > max) max = count;
});
alert(max);