The length property

Every string has a length property, which is equal to the number of characters in the string:

var str:String = "Adobe"; 
trace(str.length);            // output: 5

An empty string and a null string both have a length of 0, as the following example shows:

var str1:String = new String(); 
trace(str1.length);           // output: 0 
 
str2:String = ''; 
trace(str2.length);           // output: 0