code: function () {
  		var columns = this.columns,
  			col = columns.length, 
  			row,
  			val,
  			floatVal,
  			trimVal,
  			dateVal;
  			
  		while (col--) {
  			row = columns[col].length;
  			while (row--) {
  				val = columns[col][row];
  				floatVal = parseFloat(val);
  				trimVal = this.trim(val);
  
  				/*jslint eqeq: true*/
  				if (trimVal == floatVal) { // is numeric
  				/*jslint eqeq: false*/
  					columns[col][row] = floatVal;
  					
  					// If the number is greater than milliseconds in a year, assume datetime
  					if (floatVal > 365 * 24 * 3600 * 1000) {
  						columns[col].isDatetime = true;
  					} else {
  						columns[col].isNumeric = true;
  					}					
  				
  				} else { // string, continue to determine if it is a date string or really a string
  					dateVal = this.parseDate(val);
  					
  					if (col === 0 && typeof dateVal === 'number' && !isNaN(dateVal)) { // is date
  						columns[col][row] = dateVal;
  						columns[col].isDatetime = true;
  					
  					} else { // string
  						columns[col][row] = trimVal === '' ? null : trimVal;
  					}
  				}
  				
  			}
  		}
  	}
docs: Parse numeric cells in to number types and date types in to true dates.
  @param {Object} columns