jssubstring从右边获取指定长度字符串(示例代码)_javascript技巧

/*

Get the rightmost substring, of the specified length,

from a String object.

*/

String.prototype.right = function (length_)

{

var _from = this.length - length_;

if (_from < 0) _from = 0;

return this.substring(this.length - length_, this.length);

};