A simple bookmarklet to add an alert feature to bitcoinwisdom.com :)

alert.coffee

interval_id = high = low = null
ticker = $ '#price'
alert_url = 'http://www.angelfire.com/ut/jlpicard/images/picalert.wav'

start = ->
    do nodes.stop.show
    do nodes.start.hide
    interval_id = setInterval ->
        current_price = parseFloat do ticker.text
        unless high > current_price > low
            window.open alert_url
            do stop
        console.log "current: #{current_price}, high: #{high}, low: #{low}"
    , 1000

stop = ->
    do nodes.stop.hide
    do nodes.start.show
    if interval_id?
        clearInterval interval_id
        interval_id = null

update_values = ->
    high = parseFloat do nodes.high.val
    low = parseFloat do nodes.low.val
    alert_url = do nodes.alert.val

nodes = do ->
    left_bar = $ '#leftbar'
    context = $ """<div style="padding: 3px 7px;">
        High: <input type="text" id="high" style="width: 45px;">
        Low: <input type="text" id="low" style="width: 45px;"><br>
        Alert URL: <input type="text" id="alert_url" style="width: 100px;"><br>
        <input type="button" id="start" value="&#9654; Start">
        <input type="button" id="stop" value="&#9724; Stop">
    </div>"""
    nodes =
        high: $ '#high', context
        low: $ '#low', context
        alert: $ '#alert_url', context
        start: $ '#start', context
        stop: $ '#stop', context

    # init values
    current_price = parseFloat do ticker.text
    nodes.high.val high ? current_price * 1.05
    nodes.low.val low ? current_price * 0.95
    nodes.alert.val alert_url
    do nodes.stop.hide

    # event handlers
    nodes.start.click start
    nodes.start.click update_values
    nodes.stop.click stop
    nodes.high.change update_values
    nodes.low.change update_values
    nodes.alert.change update_values

    # write to the dom
    do left_bar.empty
    left_bar.append context

    nodes

bookmarklet.js

javascript:(function(){var e,t,n,r,i,s,o,u,a;n=t=r=null;u=$("#price");e="http://www.angelfire.com/ut/jlpicard/images/picalert.wav";s=function(){i.stop.show();i.start.hide();return n=setInterval(function(){var n;n=parseFloat(u.text());if(!(t>n&&n>r)){window.open(e);o()}return console.log("current: "+n+", high: "+t+", low: "+r)},1e3)};o=function(){i.stop.hide();i.start.show();if(n!=null){clearInterval(n);return n=null}};a=function(){t=parseFloat(i.high.val());r=parseFloat(i.low.val());return e=i.alert.val()};i=function(){var n,f,l;l=$("#leftbar");n=$('<div style="padding: 3px 7px;">\n    High: <input type="text" id="high" style="width: 45px;">\n    Low: <input type="text" id="low" style="width: 45px;"><br>\n    Alert URL: <input type="text" id="alert_url" style="width: 100px;"><br>\n    <input type="button" id="start" value="&#9654; Start">\n    <input type="button" id="stop" value="&#9724; Stop">\n</div>');i={high:$("#high",n),low:$("#low",n),alert:$("#alert_url",n),start:$("#start",n),stop:$("#stop",n)};f=parseFloat(u.text());i.high.val(t!=null?t:f*1.05);i.low.val(r!=null?r:f*.95);i.alert.val(e);i.stop.hide();i.start.click(s);i.start.click(a);i.stop.click(o);i.high.change(a);i.low.change(a);i.alert.change(a);l.empty();l.append(n);return i}()}).call(this)