Put a JavaScript to Sharepoint

i know why this doesnt work, as the link states to put it in the head section! but i presume that you dont have a head section so you would add it to the masterpage! either referencing the JS file or inline. Inline means adding it directly to the masterpage.

you never stated how your creating the page! is it a webpart or just a single aspx page with no codebehind? if it contains .cs than you can use this:

http://msdn.microsoft.com/en-us/library/vstudio/ms178207(v=vs.100).aspx

or

front end (aspx)

<input type=button value="Go" onclick="redirect" />

for the codebehind (.cs)

protected void redirect(object sender, EventArgs e)
{
    RegisterStartupScript(this, this.GetType(), "myRedirectScript", "goToNewPage();", true);
}

js file reference within masterpage:

this is within the head tag.

<script src="/_layouts/js/myRedirectPage.js" type="text/javascript"></script>

or add it directly to the masterpage

this is added directly within the head tag.

<script type="text/javascript">
function goToNewPage()
{
    var url = document.getElementById('list').value;
    if(url != 'none') {
        window.location = url;
    }
}
</script>

but this will load the JS script or file to every page unless you use a seperate masterpage

option 1

is fine but your injecting JS directly to the page, this also means its not adding JS reference to every page

option 2

this is adding to every page but you can create a copy of the masterpage just for that location to use that JS file, bit overkill as code wouldnt be called.

option 3

same as option 2

option 2 is best it does allow you to ammend the JS file without checkout of the masterpage to ammend all the time so less prone to break. Its also easy to maintain as a reference.

Try adding the code in content editor web part.