javascript window size breaks during startup

I use the following code to get the window width and height

function pageWidth() {
    return window.innerWidth != null ? window.innerWidth : document.documentElement && document.documentElement.clientWidth ? document.documentElement.clientWidth : document.body != null ? document.body.clientWidth : null;
}
fu开发者_StackOverflow社区nction pageHeight() {
    return window.innerHeight != null ? window.innerHeight : document.documentElement && document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body != null ? document.body.clientHeight : null;
}

I call this javascript during the page load. If I keep my URL as home page and try to open the explorer, I see most of the times, these function give me values equal to 0.

Any idea how to fix it? My problem is, these functions work always but if I call these functions as part of IE home page, they return 0 ( 1 in 4 case).

is there any better way of getting width of a window?

If can help i use this function that is more crossbrowser and you can call it in the event load as michael suggested

// getPageSize()
// Returns array with page width, height and window width, height
// Core code from - quirksmode.org
//
function getPageSize(){

    var xScroll, yScroll;

    if (window.innerHeight && window.scrollMaxY) {  
        xScroll = document.body.scrollWidth;
        yScroll = window.innerHeight + window.scrollMaxY;
    } else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
        xScroll = document.body.scrollWidth;
        yScroll = document.body.scrollHeight;
    } else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
        xScroll = document.body.offsetWidth;
        yScroll = document.body.offsetHeight;
    }

    var windowWidth, windowHeight;
    if (self.innerHeight) { // all except Explorer
        windowWidth = self.innerWidth;
        windowHeight = self.innerHeight;
    } else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
        windowWidth = document.documentElement.clientWidth;
        windowHeight = document.documentElement.clientHeight;
    } else if (document.body) { // other Explorers
        windowWidth = document.body.clientWidth;
        windowHeight = document.body.clientHeight;
    }   

    // for small pages with total height less then height of the viewport
    if(yScroll < windowHeight){
        pageHeight = windowHeight;
    } else { 
        pageHeight = yScroll;
    }

    // for small pages with total width less then width of the viewport
    if(xScroll < windowWidth){  
        pageWidth = windowWidth;
    } else {
        pageWidth = xScroll;
    }

    arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
    return arrayPageSize;
}

Then if the issue is the page still loading, then maybe you should wait until thats finishes before running your code:

window.addEventListener('load', function(){
  // ok, now good to call those functions and get values back!
}, false);