<button class="butt-butt" id="knopka_ok">OK</button>
document.getElementById("knopka_ok").click()
<!DOCTYPE html> <html> <head> <meta http-equiv='Content-Type' content='text/html; charset=windows-1251' /> <!-- <script src='http://code.jquery.com/jquery-latest.js'></script> <script src="https://code.angularjs.org/1.3.9/angular.min.js"></script> <script src="https://code.angularjs.org/1.3.9/angular-route.js"></script> --> <style type='text/css'> </style> <script type='text/javascript'> window.onload=function(){ document.getElementById("knopka_ok").click(); }; </script> </head> <body> <button class="butt-butt" onclick='alert("Test!")' id="knopka_ok">OK</button> </body> </html>