Running setTimeout indefinitely in JavaScript as an event handler

I building a page that will depend entirely on JavaScript. Whenever a user clicks a link or button, it changes the hash value of the URL (#doSomething).

I have setup a function the check the hash value every 200ms for changes, in other words a custom event handler, and run some code depending on what the value is. Right now it seems to be fine since I am still in the development process and my page is pretty light.

Here is my question is it ok to have a script run indefinitely checking this value? or is going to affect performance when the page has more content and 开发者_C百科stuff to work with?

Is there a better way to setup a script to detect the changes of the URL hash?

Here is my script:

var currenthash = (window.location.hash)?window.location.hash: '';
addEvent(window,'load',function () {
    if (currenthash != ''){
        hashChanged();
    }
    var timeInterval = setInterval(function () {
        if (window.location.hash != currenthash) {
            hashChanged();
            currenthash = window.location.hash;
        }
    },1000);
});

var hashChanged = function (str) {
    var id = window.location.hash.replace("#",'');
    var selected = $id(id);
    // do some more stuff

    }
}

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It shouldn't be an issue if it is checking every 1000 milliseconds (I usually run mine at 100), but consider using the native event handler (hashchange) if it exists...

if ('onhashchange' in window) {
    addEvent(window, 'hashchange', hashChanged);
} else {
   // Poll like normal.
}

This will be save you having to poll in modern browsers supporting this event.

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If the hash only changes on clicks, why not a click listener on the document, no need for setInterval or setTimeout at all and your function only runs when it needs to.

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As long as the interval isn't too short, there is no problem with it.