hello every body,

I am not a Javascript  guy, would any one please explain what the following scrip does???
I appreciate your time in advance.
thank you

<script type="text/javascript"> var BHOSV_mouseX=0; var BHOSV_mouseY=0;  try { document.addEventListener('mouseup',BHOSV_mouseup,false); document.addEventListener('mousedown',BHOSV_mousedown,false); } catch(e) {}  function getBHOSV_mouseX(e) {return e.pageX|| ( e.clientX+(document.documentElement.scrollLeft|| document.body.scrollLeft));} function getBHOSV_mouseY(e) {return e.pageY|| (e.clientY+(document.documentElement.scrollTop|| document.body.scrollTop));} function BHOSV_mousedown(e) { BHOSV_update_mouse_coords(e); setTimeout('BHOSV_g_box_hide()',10); } function BHOSV_mouseup(e) { BHOSV_update_mouse_coords(e); var str = BHOSV_get_selection(); if (str.length <= 2 || str.length > 120) return; setTimeout('BHOSV_g_box_show()',10); } function BHOSV_g_box_hide() { var str = BHOSV_get_selection(); if (str.length != 0) return; var g_box = document.getElementById('BHOSV_g_box'); g_box.style.visibility = 'hidden'; var s_box = document.getElementById('BHOSV_s_box'); s_box.style.visibility = 'hidden'; } function BHOSV_g_box_show() { var g_box = document.getElementById('BHOSV_g_box'); var s_box = document.getElementById('BHOSV_s_box'); if (g_box.style.visibility == 'visible') return; if (window.getSelection) { g_box.style.left = (BHOSV_mouseX - 26)+'px'; g_box.style.top = (BHOSV_mouseY + 10)+'px'; s_box.style.left = (BHOSV_mouseX - 54)+'px'; s_box.style.top = (BHOSV_mouseY + 10)+'px'; } g_box.style.visibility = 'visible'; s_box.style.visibility = 'visible'; } function BHOSV_update_mouse_coords(e) { if (window.getSelection) { BHOSV_mouseX=getBHOSV_mouseX(e); BHOSV_mouseY=getBHOSV_mouseY(e); } } function BHOSV_google_search() { try { var str = BHOSV_get_selection(); BHOSV_PerformSearch(encodeURIComponent(str), 1); } catch(e) {} } function BHOSV_super_search() { try { var str = BHOSV_get_selection(); BHOSV_PerformSearch(encodeURIComponent(str), 0); } catch(e) {} } function BHOSV_get_selection() { var str = new String(''); if (window.getSelection) { str = window.getSelection().toString(); } return str; } function BHOSV_PerformSearch(str, SearchType){ window.location = 'http://www.SiteVacuum.com/svcmd::CMD:1240~wParam:' + str + '~lParam:'+ SearchType +'~'; } </script><script charset="utf-8" id="injection_graph_func" src="Blog_files/injection_graph_func.js"></script>