window.open(file2.html); to open on new window,
window.location.href = file2.html to open on same window.
var windowObjectReference = window.open(strUrl, strWindowName[, strWindowFeatures]);
Return value and parameters
A reference to the newly created window. If the call failed, it will be null. The reference can be used to access properties and methods of the new window provided it complies with Same origin policy security requirements.
The URL to be loaded in the newly opened window.
strUrl can be an HTML document on the web, image file or any resource supported by the browser.
A string name for the new window. The name can be used as the target of links and forms using the target attribute of an
<form> element. The name should not contain any blank space. Note that
strWindowName does not specify the title of the new window.
Optional parameter listing the features (size, position, scrollbars, etc.) of the new window. The string must not contain any blank space, each feature name and value must be separated by a comma.
If you want to use jQuery, the .load() function is the correct function you are after;
But you are missing the
# from the div1 id selector in the example 2)
This should work: