Solutions for IEBUG and string truncation of substr _ basic knowledge

This article is a small part of this article for you to introduce the solutions for IEBUG and string truncation substr. If you need it, you can refer to it. I haven't paid attention to this problem all the time. I wanted to do this today:

The Code is as follows:

Var str = 'Hello world 8024 ';

Str. substr (-4, 4 );

A negative number is counted from the end.

Should Return: 8024

But found the IE6-IE8, The substr parameter does not support negative numbers, the returned is: hell, you can test it.

Therefore, we do not recommend using this substr method.
Use the substring method instead.

For example, str. substring (str. length-4 );
8024 is returned.