add: return null; 
context: function writeBufferLabel(parentNode, n) {    if (! parentNode)        return null;    // parentNode is a table body    var rowNode = document.createElement('tr');    var cellNode = document.createElement('td');    // set the text contents to label the new cell    cellNode.appendChild(getLabel(n));    rowNode.appendChild(cellNode);    parentNode.appendChild(rowNode);}
meta: 952	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/952/499e513a3cc333dbcb784318ca05ad90a90b7c8e/cq.js/clean/cq.js