function ChangeFrames(MyForm) {
    var atLeastOneSelected = false;
    var numberOfSelected = 0;
    var selectedOption = 0;
    for (var Current=0;Current < MyForm.SSaison.options.length;Current++) {
        if (MyForm.SSaison.options[Current].selected) {
            atLeastOneSelected = true;
            numberOfSelected += 1;
            selectedOption = Current;
        }
    }
    var atLeastOneSelected2 = false;
    var numberOfSelected2 = 0;
    var selectedOption2 = 0;
    for (var Current=0;Current < MyForm.SMonth.options.length;Current++) {
        if (MyForm.SMonth.options[Current].selected) {
            atLeastOneSelected2 = true;
            numberOfSelected2 += 1;
            selectedOption2 = Current;
        }
    }
   	//parent.main_page.location.href = MyForm.SSaison.options[selectedOption].value + MyForm.SMonth.options[selectedOption2].value;
	parent.location.href = MyForm.SSaison.options[selectedOption].value + MyForm.SMonth.options[selectedOption2].value;
}
<!--
function ChangeFramesYearsOnly(MyForm) {
    var atLeastOneSelected = false;
    var numberOfSelected = 0;
    var seletedOption = 0;
    for (var Current=0;Current < MyForm.SSaison.options.length;Current++) {
        if (MyForm.SSaison.options[Current].selected) {
            atLeastOneSelected = true;
            numberOfSelected += 1;
            selectedOption = Current;
        }
    }
    	//parent.main_page.location.href = MyForm.SSaison.options[selectedOption].value;
		parent.location.href = MyForm.SSaison.options[selectedOption].value;
}
//-->