Include JS in iframe with DOM

[114v]

Hi

I have HTML file:

<iframe src="http://domain.com/text.html"></iframe> 

Javascript code:

function js_include(sFileName){
var objHead = document.getElementsByTagName('head');
var objScript = document.createElement('script');
objScript.type = 'text/javascript';
objScript.src = sFileName;
objHead[0].appendChild(objScript);
} 

I need include js in iframe. Example:

js_include('text.js') 

Content of text.js:

document.write("Text in iframe"); 

When iframe will have: Text in iframe

I get element of iframe with code:

var elements;
if(document.getElementsByTagName) {
    elements = document.body.getElementsByTagName("IFRAME");
} else if (document.body.all) {
    elements = document.body.all.tags("IFRAME");
} else {
    elements = Array();
}
for(var i = 0; i < elements.length; i++) {
    if(elements[i].src.indexOf('text.html') > -1) {
        // Please help me here, how to include js in iframe which src have text.html. Thanks
    }
} 

[114v]

Help me please!