Adding button on CRM Form

We all know that CRM gives some listed attributes(fields).
Suppose we need a button(which is not avail in MS CRM as attribute), suppose for any purpose like onclick of button another pop-up will open(which can save a tab,ofcourse).

>> for this we need a place holder(suppose a textbox) named new_buttonName.

//this will create a button with label "Click 4 Pop-up" inplace of the place holder(textbox)
if(crmForm.all.new_buttonName != null){
crmForm.all.new_buttonName_d.innerHTML = '';
crmForm.all.searchButton.attachEvent("onclick", _openPopup);
crmForm.all.sdv_googlelocationbutton_c.innerHTML = " ";
}

//this function will be called on click of the button created earlier
function _openPopup(){
window.open("http://positiveedge.net","PositiveEdge","height=500,width=950,scrollbars=1");
}