Remove first and last empty lines, remove useless indentation. Good for parsing HTML
var str = '\n\n\n Multiline text\n with indentation\n damn.\n\n\n';
// remove first and last empty lines
str = str.replace(/^[\r\n]+|[\n\r]+$/gi, '');
var indentTab = str.match(/\t*/) != '',
indentSize = indentTab ? 1 : str.match(/\s*/)[0].length,
regex = new RegExp('^(?:' + (indentTab ? '\\t' : ' {' + indentSize + '}') + ')', 'mg');
// Remove indent
if (indentSize)
str = str.replace(regex, '');