Difference between getelementsbytagname and $ (é lement)

The getelementsbytagname of JS and $ (élement) of JQ both get the elements in Dom, but they also have some differences and paste the Code:

VaR El = Document. getelementsbytagname ('P ');
VaR P = '<P class = "AA"> </P> ';
$ ('Body'). append (P );
Console. Log (El. Length) // P Tag Length + 1;

 

VaR El = $ ('P ');
VaR P = '<P class = "AA"> </P> ';
$ ('Body'). append (P );
Console. Log (El. Length) // The length of the P tag is the original Dom length.

 

In this way, we can see that when an element is added to the Dom, The getelementsbytagname set automatically updates the number of elements, while $ (é lement) is still the snapshot of the original element set.

Difference between getelementsbytagname and $ (é lement)