function ChangeFormAction(str)
{
    var arr = new Array();
    arr[0] = 'web';
    arr[1] = 'image';
    arr[2] = 'movie';
    arr[3] = 'domain';

    for (i = 0; i < arr.length; i++) {
        if (arr[i] == str) {
            document.getElementById(arr[i] + '_txt').style.fontWeight = 'bold';
            document.getElementById(arr[i] + '_txt').style.color = 'black';
        } else {
            document.getElementById(arr[i] + '_txt').style.fontWeight = 'normal';
            document.getElementById(arr[i] + '_txt').style.color = 'blue';
        }
    }

    if (str == 'image') {
        document.getElementById('act').name  = 'act';
        document.getElementById('act').value = 'image';
    }else if (str == 'movie') {
        document.getElementById('act').name  = 'act';
        document.getElementById('act').value = 'movie';
    }else if (str == 'domain') {
        document.getElementById('act').name  = 'domain';
        document.getElementById('act').value = 'www.wbs.ne.jp';
    } else {
        document.getElementById('act').name  = '';
        document.getElementById('act').value = '';
    }
}