Largest item in an array

Largest item in an array

I have the following code from another answer here on Stackoverflow:
var myarray = ['a','abcde','ab'];
var maxlen = 0;
for (i=0; i<myarray.length; i++) {
if (myarray[i].length>maxlen) {
maxlen = myarray[i].length;
}
}
I understand everything about this, apart from why creating a maxlen = 0
and then using the if operator selects the largest length.
Surely because ab is also larger than 0, that could also become the
variable maxlen? Why was abcde chosen instead?