Compare two xml values using ajax

Question

OK, so I'm trying to monitor and control something with a Pic-web from microchip. I managed to program it all except for one thing. I need to compare two temperatures that it gives me, and if one of them is smaller that the other then a relay needs to be activated, if its bigger or equal then another relay must be activated. From what I understood Pic-web updates an xml file (status.xml) then the website (using ajax) takes the values from there and displays them on the web page.

The XML file looks like this

<response>
<temp0>~temp~</temp0>
<temp2>~tempc~</temp2>
</response

The ajax code I use to get the values in my web page

document.getElementById('temp0').innerHTML = getXMLValue(xmlData, 'temp0');
document.getElementById('temp2').innerHTML = getXMLValue(xmlData, 'temp2');

And to display them I use

<span id="temp0"style="font-weight:normal">?</span>
<span id="temp2"style="font-weight:normal">?</span>

All I need to do is to compare temp0 with temp2

    var temp0 = parseFloat(document.getElementById('temp0').innerHTML)
    var temp2 = parseFloat(document.getElementById('temp2').innerHTML)

    if( temp0 < temp2 ) 
    {
        document.getElementById('temp3').innerHTML = '<font color="#00FF00">ON</font>';
    } 
    else 
    {
        document.getElementById('temp3').innerHTML = '<font color="#00FFFF">OFF</font>';

}

The I just add <span id="temp3">?</span> to display the result

Am I correct?

Diodeus - James MacFarlane · Accepted Answer · 2012-06-19 16:27:05Z

1

if(getXMLValue(xmlData, 'temp0') < 'temp2')

'temp0' is not the value of document.getElementById('temp0'), it's just a string you made up containing 'temp0'.

You need to assign this to a variable and convert it to a number from a string:

var temp0 = parseFloat(document.getElementById('temp0').innerHTML)
var temp2 = parseFloat(document.getElementById('temp2').innerHTML)

Then use:

if(temp0 < temp2)

answered Jun 19, 2012 at 16:27

Diodeus - James MacFarlane

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Comments

freefaller · Accepted Answer · 2012-06-19 16:26:05Z

0

This line looks incorrect...

if(getXMLValue(xmlData, 'temp0') < 'temp2')

Should it be...?

if(getXMLValue(xmlData, 'temp0') < getXMLValue(xmlData, 'temp2'))

And unless getXMLValue returns a number of some variety, you will want want to convert it before comparing

answered Jun 19, 2012 at 16:26

freefaller

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Comments

Ryan · Accepted Answer · 2012-06-19 16:27:46Z

0

What about something like this:

var temp0 = parseInt(getXMLValue(xmlData, 'temp0'))
  , temp2 = parseInt(getXMLValue(xmlData, 'temp2'));

if( temp0 < temp2 ) {
    ...
} else {
    ...
}

answered Jun 19, 2012 at 16:27

Ryan

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Comments

Pascan Sorin · Accepted Answer · 2012-06-21 11:16:10Z

// Compare the two temperatures
var temp0 = parseFloat(document.getElementById('temp0').innerHTML)
var temp2 = parseFloat(document.getElementById('temp2').innerHTML)

if( temp0 < temp2 ) {
    document.getElementById('temp3').innerHTML = '<font color="#00FF00">ON</font>';
} else {
    document.getElementById('temp3').innerHTML = '<font color="#FF0000">OFF</font>';
}

This will display ON if temp2 > temp0

and OFF if temp0 < temp2

thank all of you for your support

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