Type-Checking Your Data

The Yahoo Global Object includes several useful type-checking methods in the YAHOO.lang object. Click the Check button in each row to evaluate the data.

Data isObject isArray isFunction
null
[] or new Array()
{} or new Object()
function Foo() {}
new Foo()
elem.getElementsByTagName('p')
YAHOO.util.Dom. getElementsByClassName(
'foo','p',elem)