Php and JavaScript Bugs Found

Hello.
In trouble shooting the compatibility of our two plugins, I found a few bugs that you might like to know about.

1. file: simplepagetester.php
function sptDetailsMeta()
around line: 257
you are simply echoing count($sptData[$sptData['master_id'] . '_visits']); with out first checking to see if it has been set.
Before:

echo '			</select> %
				</td>
			</tr>
			<tr>
				<th scope="row" colspan="1">Total Unique Visits:</th>
				<td colspan="2">' . count($sptData[$sptData['master_id'] . '_visits']) . '</td>
			</tr>';

After:

echo '</select> % </td></tr>
	<tr><th scope="row" colspan="1">Total Unique Visits:</th><td colspan="2">';
if( !empty($sptData[$sptData['master_id'] . '_visits']) ){
		echo count($sptData[$sptData['master_id'] . '_visits']);
}
echo '</td></tr>';

2. Same file, same issue around line 302:
Before:

<td colspan="2">' . count($sptData[$sptData['slave_id'] . '_visits']) .

After:

<td colspan="2">';
if( !empty( $sptData[$sptData['slave_id'] . '_visits'] ) ){
		echo count($sptData[$sptData['slave_id'] . '_visits']);
}

3. same file
function: sptRecordVisit()
around line 506
session_start() is throwing an error because the session has already been started. either remove this or check before starting the session.

//session_start();

4. same file, same function, around line 531:
Before:

'ip' => getenv(REMOTE_ADDR)

After:

'ip' => getenv('REMOTE_ADDR')

5. file: sptHelper.js
function: sptDrawChart
around lines 66 and 71
not checking first to see if the variable has been set.
Before:

if (chart_data[0].length == 5)

After:

if (chart_data[0].length && chart_data[0].length == 5)

https://wordpress.org/plugins/simple-page-tester/