javascript(substr与substring)，substrsubstring

javascript(substr与substring)，substrsubstring

还有一点区别是百度经验上没有说到的，这里

var test = "hello";

var a = "";

a = test.substring(0,3); a=hel

a = test.substr(0,3);  a=hel

a = test.substring(1,3); a=el

a = test.substr(1,3);  a=ell