How to handle empty XML fields in JS

[iandunn]

I'm using JavaScript to retrieve info from an XML file, but if any of the fields are empty I get this error:

Error: xmlDocument.getElementsByTagName("address2Title")(0).firstChild has no propertiesSource File: http://localhost/contactManager/Line: 47

Here's an example of the XML file:

<contact>  <id>2</id>  <firstName>First Name</firstName>  <lastName>Last Name</lastName>  <address1Title>Home</address1Title>  <address1>101 Blah St</address1>  <city1>Dayton</city1>  <state1>Ohio</state1>  <zipCode1>45402</zipCode1>  <address2Title/>  <address2/>  <city2/>  <state2/>  <zipCode2/>  <homePhone>9375559407</homePhone>  <cellPhone>9375556845</cellPhone>  <workPhone/>  <birthday>01311978</birthday></contact>

And here's the relevant JS code

document.getElementById("contactInfo").innerHTML = xmlDocument.getElementsByTagName('firstName').item(0).firstChild.nodeValue +xmlDocument.getElementsByTagName('lastName').item(0).firstChild.data +xmlDocument.getElementsByTagName('address1Title').item(0).firstChild.data +xmlDocument.getElementsByTagName('address1').item(0).firstChild.data +xmlDocument.getElementsByTagName('city1').item(0).firstChild.data +xmlDocument.getElementsByTagName('state1').item(0).firstChild.data +xmlDocument.getElementsByTagName('zipCode1').item(0).firstChild.data +xmlDocument.getElementsByTagName('address2Title')(0).firstChild.nodeValue +xmlDocument.getElementsByTagName('address2').item(0).firstChild.data +xmlDocument.getElementsByTagName('city2').item(0).firstChild.data +xmlDocument.getElementsByTagName('state2').item(0).firstChild.data +xmlDocument.getElementsByTagName('zipCode2').item(0).firstChild.data +xmlDocument.getElementsByTagName('homePhone').item(0).firstChild.data +xmlDocument.getElementsByTagName('cellPhone').item(0).firstChild.data +xmlDocument.getElementsByTagName('workPhone').item(0).firstChild.data +xmlDocument.getElementsByTagName('birthday').item(0).firstChild.data;

Is there a way to access the field that won't cause an error if it's empty, or is there a way to check if it's empty before trying to use it?

[Webworldx]

var fields = [ "firstName" , "lastName" , "addressTitle" , "address1" , "city1" ];var content = ""for(i = 0; i < fields.length; i++){ if(xmlDocument.getElementsByTagName(fields[i]).item(0).firstChild.data){   content += xmlDocument.getElementsByTagName(fields[i]).item(0).firstChild.data }}document.getElementById("contactInfo").innerHTML = content

Something like that?