//```ops
//title:一些常用的js方法
//descr:
//```

/**
 * @label:判断字符串是否一以xx开头
 */
String.prototype.startsWith = function(s) {
    if (s == null || s == "" || this.length == 0 || s.length > this.length)
        return false;
    if (this.substr(0, s.length) == s)
        return true;
    else
        return false;
    return true;
}

/**
 * @label:判断字符串是否一以xx结尾
 */
String.prototype.endsWith = function(s) {
    if (s == null || s == "" || this.length == 0 || s.length > this.length)
        return false;
    if (this.substring(this.length - s.length) == s)
        return true;
    else
        return false;
    return true;
}