js removeChild blindfold possible errors_javascript skills

There is a structure:

Copy code The code is as follows:

• a


• b


• c

If you run code 1:

Copy code The code is as follows:

var ul = document.getElementById('demo');
var liList = ul.getElementsByTagName('li');
for (var i = 0; i < = liList.length; i ) {
ul. removeChild(liList[i]);
}

If you were deceived like me, then you will understand the reason after looking at the correct code!

Copy code The code is as follows:

var ul = document.getElementById('demo');
var liList = ul.getElementsByTagName('li');
var lilength = liList.length;
for (var i = 0; i < lilength; i ) {
ul.removeChild( liList[0]);
}