在特定的情况下，你可以只是一个无聊的老计数器做到这一点：

In your specific case, you can do it just with a boring old counter:

var index, value, result;
for (index = 0; index < windowArray.length; ++index) {
    value = windowArray[index];
    if (value.substring(0, 3) === "id-") {
        // You've found it, the full text is in `value`.
        // So you might grab it and break the loop, although
        // really what you do having found it depends on
        // what you need.
        result = value;
        break;
    }
}

// Use `result` here, it will be `undefined` if not found

但如果你的数组是的稀疏的，你可以做到这一点更有效地与正确设计的的for..in 循环：

var key, value, result;
for (key in windowArray) {
    if (windowArray.hasOwnProperty(key) && !isNaN(parseInt(key, 10))) {
        value = windowArray[key];
        if (value.substring(0, 3) === "id-") {
            // You've found it, the full text is in `value`.
            // So you might grab it and break the loop, although
            // really what you do having found it depends on
            // what you need.
            result = value;
            break;
        }
    }
}

// Use `result` here, it will be `undefined` if not found

谨防没有那么幼稚的for..in 环路的hasOwnProperty 和 ！isNaN（parseInt函数（键，10））检查; 这里的原因。

题外话

另一种方式来写

var windowArray = new Array ("item","thing","id-3-text","class");

是

var windowArray = ["item","thing","id-3-text","class"];

...这是你少打字，也许（这一点是主观的）多一点轻松阅读。这两个语句具有完全相同的结果：与内容的新数组

...which is less typing for you, and perhaps (this bit is subjective) a bit more easily read. The two statements have exactly the same result: A new array with those contents.