function pwBindReady(handler) {
    var called = false

    function ready() {
        if(called) return
        called = true
        handler()
    }
    if(document.addEventListener) {
        document.addEventListener("DOMContentLoaded", function() {
            ready()
        }, false)
    } else if(document.attachEvent) {
        if(document.documentElement.doScroll && window == window.top) {
            function tryScroll() {
                if(called) return
                if(!document.body) return
                try {
                    document.documentElement.doScroll("left")
                    ready()
                } catch(e) {
                    setTimeout(tryScroll, 0)
                }
            }
            tryScroll()
        }
        document.attachEvent("onreadystatechange", function() {
            if(document.readyState === "complete") {
                ready()
            }
        })
    }
    if(window.addEventListener) window.addEventListener('load', ready, false)
    else if(window.attachEvent) window.attachEvent('onload', ready)
}