GM_getValue未定义错误 [英] GM_getValue undefined error

问题描述

在我的oilmonkey脚本中，我想检查GM值:用户名和密码是否已设置，但是当我尝试以下代码时，它会给我返回错误消息:

In my greasemonkey script I want to check if the GM Value : Username and Password isset but when i try the following code it gives me back the error :

TypeError: GM_getValue(...) is undefined    
...f (GM_getValue ("username").length == 0 + GM_getValue ("password").length == 0 )

代码:

if (GM_getValue ("username").length == 0 + GM_getValue ("password").length == 0 ){
var username = $('input[name=username]');
var password = $('input[name=password]');

//Username en Password in Firefox zetten met GM_setValue
$(".button").click(function(){

GM_setValue ("username", username.val() );
GM_setValue ("password", password.val() );

});
}

推荐答案

GM_getValue不返回数组，并且没有length属性.
如果未设置该值，则该函数返回undefined.进行检查的正确方法是:

GM_getValue does not return an array and does not have a length property.
That function returns undefined if the value was not set. The proper way to do the check you are attempting is:

var uName = GM_getValue ("username", "");
var pWord = GM_getValue ("password", "");

if ( ! uName   &&  ! pWord) {
    uName = $('input[name=username]').val();
    pWord = $('input[name=password]').val();
}

1. 该错误消息(如果尚未进行编辑)表明该脚本未正确激活GM_getValue. 必须设置适当的@grant值才能使用GM_函数. EG:

1. That error message (if it hasn't been edited) suggests that the script did not activate GM_getValue properly. You must set appropriate @grant values to use GM_ functions. EG:

// @grant    GM_getValue
// @grant    GM_setValue

您正在使用的方法:

The approach you are starting:

• 有错误-因此需要这个问题.
• 存在您会发现的可用性问题.
• 没有便利或安全功能.
  

• Has errors -- hence the need for this question.
• Has usability problems which you will discover.
• Doesn't have convenience or security features.
  

因此，不要在没有充分理由的情况下重新发明轮子.已经有经过验证的，更安全的，功能齐全的框架可用于此类操作. 这是一个好人.

So, don't reinvent the wheel without a darn good reason. There are already proven, more-secure, full-featured frameworks for this kind of thing. Here's a good one.

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