带有JSON对象的JavaScript范围

Question

单击元素时将调用此函数。 它根据单击的元素创建一个字符串，然后在JSON对象中查找与该字符串关联的值。 然后它会提醒该值。 以下是它的外观：

function alertHelp(){
    var option = $(this).context.parentNode.textContent.substring(0, $(this).context.parentNode.textContent.length - 2);
    $.getJSON("Messages.json", function(json, option) {
        alert(json[option]);
    });
}

我发现该选项设置正确，但是当传递给函数时，警报被更改。 如果我在alert(json[object]);之前alert(option) alert(json[object]); ，我得到一个简单地说“成功”的警报。 不确定是什么。 alert(json[option])只是警告“未定义”。

这是Messages.json：

{
    "Space Control": "Red = a square black controls. Green = a square white controls. Yellow = a square contested by both players",
    "Legal Moves": "Click on a piece and a blue dot will appear on all the squares that piece can move to",
    "PieceFlair": "When you move a piece, all the pieces that come under attack as a direct result of the piece you moved will pulse white",
    "Forks": "All the moves that would result in a simultaneous attack of two pieces are shown",
    "Pins": "Not yet implemented"
}

Answer 1

你已经通过function参数option “遮蔽”你的var option option ，试试这个：

var text = $(this).context.parentNode.textContent;
var option = text.substring(0, text.length - 2);

$.getJSON("Messages.json", function(json, status) {
    alert(status);  // success
    alert(json[option]);
});