jQuery.isJson = function(str) {
	if (jQuery.trim(str) == '') return false;
	str = str.replace(/\\./g, '@').replace(/"[^"\\\n\r]*"/g, '');
	return (/^[,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t]*$/).test(str);     
}
jQuery.truncate = function(str, options) {
	settings = jQuery.extend({len: 30,
														truncation: '...'
														}, options);
	if(typeof str == 'undefined' || jQuery.trim(str) == '') return '';
	return str.length > settings.len ? str.slice(0, settings.len - settings.truncation.length) + settings.truncation : str;
}