JavaScript - 字符串截取函数substr()与substring()的区别

<script type="text/javascript">
	/*
		substr(start, number);
		start - 起始位置，下标从0开始
		number - 截取几个字符
	*/
	function substrDemo(){
		var str = "123 abc..";
		var s = str.substr(2, 6);
		return s; //3 abc.
	}
	alert(substrDemo());

	/*
		substring(start, end);
		start - 起始位置，下标从0开始
		end - 结束位置，下标-1
	*/
	function substringDemo(){
		var str = "123 abc..";
		var s = str.substring(2, 6); //3 ab
		return s;
	}
	alert(substringDemo());
</script>