function onClick()
{
    document.search_form.Data_Entry.value="";
}

function onLoad()
{
    var Current = document.search_form.Search_Type.selectedIndex;
    var currentText = document.search_form.Search_Type.options[Current].text;
    var currentValue = document.search_form.Search_Type.options[Current].value;

    switch (currentValue)
    {
        case   "Search_Details":
            document.search_form.Start_Year.disabled=true;
            document.search_form.Finish_Year.disabled=true;
            document.search_form.Data_Entry.disabled= false;
            document.search_form.Data_Entry.select();
            document.search_form.Data_Entry.focus();
            break;

        case "First_Name":
            document.search_form.Start_Year.disabled=true;
            document.search_form.Finish_Year.disabled=true;
            document.search_form.Data_Entry.disabled= false;
            document.search_form.Data_Entry.select();
            document.search_form.Data_Entry.focus();
            break;

        case "Last_Name":
            document.search_form.Start_Year.disabled=true;
            document.search_form.Finish_Year.disabled=true;
            document.search_form.Data_Entry.disabled= false;
            document.search_form.Data_Entry.select();
            document.search_form.Data_Entry.focus();
            break;

        case "Period_at_School":
            document.search_form.Start_Year.disabled=false;
            document.search_form.Finish_Year.disabled=false;
            document.search_form.Data_Entry.disabled= true;
            document.search_form.Data_Entry.value="";
            break;

        default:
            document.search_form.Start_Year.disabled=true;
            document.search_form.Finish_Year.disabled=true;
            document.search_form.Data_Entry.disabled= true;
            document.search_form.Data_Entry.value="";
            break;
    }
}

function onChange()
{
    var Current = document.search_form.Search_Type.selectedIndex;
    var currentText = document.search_form.Search_Type.options[Current].text;
    var currentValue = document.search_form.Search_Type.options[Current].value;


    switch (currentValue)
    {
        case   "Search_Details":
            document.search_form.Start_Year.disabled=true;
            document.search_form.Finish_Year.disabled=true;
            document.search_form.Data_Entry.disabled= false;
            document.search_form.Data_Entry.select();
            document.search_form.Data_Entry.focus();
            break;
        
        case "First_Name":
            document.search_form.Start_Year.disabled=true;
            document.search_form.Finish_Year.disabled=true;
            document.search_form.Data_Entry.disabled= false;
            document.search_form.Data_Entry.select();
            document.search_form.Data_Entry.focus();
            break;

        case "Last_Name":
            document.search_form.Start_Year.disabled=true;
            document.search_form.Finish_Year.disabled=true;
            document.search_form.Data_Entry.disabled= false;
            document.search_form.Data_Entry.select();
            document.search_form.Data_Entry.focus();
            break;

        case "Period_at_School":
            document.search_form.Start_Year.disabled=false;
            document.search_form.Finish_Year.disabled=false;
            document.search_form.Data_Entry.disabled= true;
            document.search_form.Data_Entry.value="";
            break;

        default:
            document.search_form.Start_Year.disabled=true;
            document.search_form.Finish_Year.disabled=true;
            document.search_form.Data_Entry.disabled= true;
            document.search_form.Data_Entry.value="";
            break;
    }

}

function validateFormOnSubmit(form_field)
{		
    var regExp_name = /^[a-zA-Z\s]{3,30}$/;
    var regExp_search = /^[\w\W\s]{3,100}$/;

    if (document.search_form.Search_Type.selectedIndex == -1)
    {
        alert("Select a Search Option");
        form_field.Start_Year.focus();
        return false;
    }
	
    if (document.search_form.Search_Type.value == "Search_Details")
    {
        if (!regExp_search.test(form_field.Data_Entry.value))
        {
            alert("Please enter your search criteria\r\nThe search string must be between 3 and 100 letters long.")
            form_field.Data_Entry.focus()
            form_field.Data_Entry.select()
            return false
        }
		
        return true
    }

	
    if (document.search_form.Search_Type.value == "First_Name")
    {
        if (!regExp_name.test(form_field.Data_Entry.value))
        {
            alert("Please enter the Christian name\r\nThe Christian name must be between 3 and 30 letters long.")
            form_field.Data_Entry.focus()
            form_field.Data_Entry.select()
            return false
        }
		
        return true
    }
	
    if (document.search_form.Search_Type.value == "Last_Name")
    {
        if (!regExp_name.test(form_field.Data_Entry.value))
        {
            alert("Please enter the Surname\r\nThe Surname must be between 3 and 30 letters long.")
            form_field.Data_Entry.focus()
            form_field.Data_Entry.select()
            return false
        }
		
        return true
    }
	
    if (document.search_form.Search_Type.value == "Period_at_School")
    {
	
        if (document.search_form.Start_Year.selectedIndex == -1)
        {
            alert("Select a start year");
            form_field.Start_Year.focus();
            return false;
        }
		
		
        if (document.search_form.Finish_Year.selectedIndex == -1)
        {
            alert("Select a finish year");
            form_field.Finish_Year.focus();
            return false;
        }
		
        if (document.search_form.Finish_Year.value < document.search_form.Start_Year.value)
        {
            alert("The Start Year you have selected "+ document.search_form.Start_Year.value +", must be before your Finish Year " + document.search_form.Finish_Year.value );
            return false;
        }
		
        return true;
	
    }

}