密码规则校验

1.必须包含数字、下划线、字母，而且可以指定密码长度范围

checkout.pwdCheck = function( str,minLen,maxLen ){
    var
    i,str = str + '',minLen = minLen || 0,len = str.length,maxLen = maxLen || len + 1,// 防止 maxLen 不传报错
    pwdReg = [ /\d+?/g,/\w+?/g,/\_+?/g ];

    if( minLen > len && maxLen < len || /\s+?/g.test( str ) ) return false;
    for( i = 0; i < pwdReg.length; i++ ){
        if ( !pwdReg[i].test( str ) )  return false;
    }
    return true;
};