i have a sample html file.
<html>
    <head>
        <script src="sample1.js"></script>
    </head>
    <body>
        <iframe id="sif" src="if.html"></iframe>
    </body>
</html>
how can add text or elements in the if.html with sample1.js? 
i have a sample html file.
<html>
    <head>
        <script src="sample1.js"></script>
    </head>
    <body>
        <iframe id="sif" src="if.html"></iframe>
    </body>
</html>
how can add text or elements in the if.html with sample1.js? 
thanks  kingdamian42.
yes its work.  
sample1.js
function getFrameContents()
{
    var iFrame =  document.getElementById('sif');
    var iFrameBody;
    if ( iFrame.contentDocument ) 
    { // FF
        iFrameBody = iFrame.contentDocument.getElementsByTagName('body')[0];
    }
    else if ( iFrame.contentWindow ) 
    { // IE
        iFrameBody = iFrame.contentWindow.document.getElementsByTagName('body')[0];
    }
    alert(iFrameBody.innerHTML);
}