javascript 合并相同表格

function mergerTd(tableId,rowNum){
	var tableObj = document.getElementById(tableId);
	var rowsObj = tableObj.rows;
	var rowIndex = rowsObj.length;
	var baseRowNum = 0;
	var mergerLength = 0;
	var textStr = "";
	for(var i=0;i<rowIndex;i++){
		var cellsObj = rowsObj[i].cells;
		if(rowsObj[i].cells[rowNum] && rowsObj[i].cells[rowNum].innerHTML){
			var rowSpanLength = rowsObj[i].cells[rowNum].rowSpan;
			if(rowSpanLength && rowSpanLength > 1){
				i=i+rowSpanLength-1;
			}
			if(cellsObj[rowNum].innerText == textStr){
				if(rowSpanLength && rowSpanLength > 1){
					mergerLength=mergerLength+rowSpanLength
				}else{
					mergerLength++;
				}
			}else{
				if(mergerLength > 0){
					rowsObj[baseRowNum].cells[rowNum].rowSpan = mergerLength+1;
					for(var j=1;j<=mergerLength;j++){
						rowsObj[baseRowNum+j].cells[rowNum].style.display = "none";
					}
				}
				baseRowNum = i;
				mergerLength = 0;
				textStr = cellsObj[rowNum].innerText;
			}
		}		
	}
	if(mergerLength > 0){
		rowsObj[baseRowNum].cells[rowNum].rowSpan = mergerLength+1;
		for(var j=1;j<=mergerLength;j++){
			rowsObj[baseRowNum+j].cells[rowNum].style.display = "none";
		}
	}
}