function trim(s)
{
    var i,j;
    for (i = 0; i < s.length && s.charAt(i) == " "; i++);
    for (j = s.length-1; j >= 0 && s.charAt(j) == " "; j--);
    if (i<=j)
        return s.substring(i, j+1);
    else
        return '';
}
function CheckValue(thisname, sourse_text)
{
    var keyword_value = trim(thisname.value);
    if (keyword_value=='')
        thisname.value=sourse_text;
}
function HideValue(thisname, sourse_text)
{
    var keyword_value = trim(thisname.value);
    if (keyword_value==sourse_text)
        thisname.value='';
}