如何可靠地偵測不同瀏覽器之間的瀏覽器後退按鈕按下情況？

document.onmouseover = function() {
    // User's cursor is within the document area
    window.innerDocClick = true;
}

document.onmouseleave = function() {
    // User's cursor has exited the document area
    window.innerDocClick = false;
}

window.onhashchange = function() {
    if (window.innerDocClick) {
        // Navigation triggered by in-page action
    } else {
        // Browser back button was pressed
    }
}

$(function(){
    var rx = /INPUT|SELECT|TEXTAREA/i;
    $(document).bind("keydown keypress", function(e){
        if( e.which == 8 ){ // 8 == backspace
            if(!rx.test(e.target.tagName) || e.target.disabled || e.target.readOnly ){
                e.preventDefault();
            }
        }
    });
});