XML parsing of a variable string in JavaScript

Question

I have a variable string that contains well-formed and valid XML  I need to use JavaScript code to parse this feed   How can I accomplish this using  browser-compatible  JavaScript code

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Most examples on the web  and some presented above  show how to load an XML from a file in a browser compatible manner  This proves easy  except in the case of Google Chrome which does not support the document implementation createDocument   method  When using Chrome  in order to load an XML file into a XmlDocument object  you need to use the inbuilt XmlHttp object and then load the file by passing it s URI   In your case  the scenario is different  because you want to load the XML from a string variable  not a URL  For this requirement however  Chrome supposedly works just like Mozilla  or so I ve heard  and supports the parseFromString   method   Here is a function I use  it s part of the Browser compatibility library I m currently building    function LoadXMLString xmlString         ObjectExists checks if the passed parameter is not null       isString  as the name suggests  checks if the type is a valid string    if  ObjectExists xmlString   amp  amp  isString xmlString           var xDoc         The GetBrowserType function returns a 2-letter code representing           the type of browser      var bType   GetBrowserType         switch bType              case  ie              This actually calls into a function that returns a DOMDocument             on the basis of the MSXML version installed             Simplified here for illustration          xDoc   new ActiveXObject  MSXML2 DOMDocument           xDoc async   false          xDoc loadXML xmlString           break        default          var dp   new DOMParser            xDoc   dp parseFromString xmlString   text xml            break            return xDoc        else     return null

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I ve always used the approach below which works in IE and Firefox   Example XML    lt fruits gt     lt fruit name  Apple  colour  Green    gt     lt fruit name  Banana  colour  Yellow    gt   lt  fruits gt    JavaScript   function getFruits xml      var fruits   xml getElementsByTagName  fruits   0     if  fruits        var fruitsNodes   fruits childNodes      if  fruitsNodes          for  var i   0  i  lt  fruitsNodes length  i              var name   fruitsNodes i  getAttribute  name            var colour   fruitsNodes i  getAttribute  colour            alert  Fruit     name     is coloured     colour

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Apparently jQuery now provides jQuery parseXML http   api jquery com jQuery parseXML  as of version 1 5  jQuery parseXML  data   Returns  XMLDocument

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Please take a look at XML DOM Parser  W3Schools   It s a tutorial on XML DOM parsing  The actual DOM parser differs from browser to browser but the DOM API is standardised and remains the same  more or less    Alternatively use E4X if you can restrict yourself to Firefox  It s relatively easier to use and it s part of JavaScript since version 1 6  Here is a small sample usage       Using E4X var xmlDoc new XML    xmlDoc load  note xml    document write xmlDoc body     Note   body  is actually a tag in note xml    but it can be accessed as if it were a regular property of xmlDoc

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Updated answer for 2017  The following will parse an XML string into an XML document in all major browsers  Unless you need support for IE  lt   8 or some obscure browser  you could use the following function     function parseXml xmlStr       return new window DOMParser   parseFromString xmlStr   text xml        If you need to support IE  lt   8  the following will do the job     var parseXml   if  typeof window DOMParser     undefined         parseXml   function xmlStr            return new window DOMParser   parseFromString xmlStr   text xml             else if  typeof window ActiveXObject     undefined   amp  amp         new window ActiveXObject  Microsoft XMLDOM          parseXml   function xmlStr            var xmlDoc   new window ActiveXObject  Microsoft XMLDOM            xmlDoc async    false           xmlDoc loadXML xmlStr           return xmlDoc           else       throw new Error  No XML parser found        Once you have a Document obtained via parseXml  you can use the usual DOM traversal methods properties such as childNodes and getElementsByTagName   to get the nodes you want   Example usage   var xml   parseXml   lt foo gt Stuff lt  foo gt     alert xml documentElement nodeName     If you re using jQuery  from version 1 5 you can use its built-in parseXML   method  which is functionally identical to the function above   var xml     parseXML   lt foo gt Stuff lt  foo gt     alert xml documentElement nodeName

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Marknote is a nice lightweight cross-browser JavaScript XML parser  It s object-oriented and it s got plenty of examples  plus the API is documented  It s fairly new  but it has worked nicely in one of my projects so far  One thing I like about it is that it will read XML directly from strings or URLs and you can also use it to convert the XML into JSON   Here s an example of what you can do with Marknote   var str     lt books gt                   lt book title  A Tale of Two Cities   gt                   lt book title  1984   gt                 lt  books gt     var parser   new marknote Parser    var doc   parser parse str    var bookEls   doc getRootElement   getChildElements     for  var i 0  i lt bookEls length  i          var bookEl   bookEls i          alerts  Element name is  book  and book title is            alert  Element name is      bookEl getName                 and book title is               bookEl getAttributeValue  title

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You can also through the jquery function   parseXML  to manipulate xml string  example javascript   var xmlString     lt languages gt  lt language name  c  gt  lt  language gt  lt language name  php  gt  lt  language gt  lt  languages gt    var xmlDoc     parseXML xmlString     xmlDoc  find  name   each function        console log  name     this  attr  name

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Disclaimer   I ve created fast-xml-parser  I have created fast-xml-parser to parse a XML string into JS JSON object or intermediate traversal object  It is expected to be compatible in all the browsers  however tested on Chrome  Firefox  and IE only    Usage  var options       default     attrPrefix             attrNodeName  false      textNodeName     text       ignoreNonTextNodeAttr   true      ignoreTextNodeAttr   true      ignoreNameSpace   true      ignoreRootElement   false      textNodeConversion   true      textAttrConversion   false      arrayMode   false     if parser validate xmlData     optional     var jsonObj   parser parse xmlData  options        Intermediate obj var tObj   parser getTraversalObj xmlData options     var jsonObj   parser convertToJson tObj     Note  It doesn t use DOM parser but parse the string using RE and convert it into JS JSON object   Try it online  CDN

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Update  For a more correct answer see Tim Down s answer   Internet Explorer and  for example  Mozilla-based browsers expose different objects for XML parsing  so it s wise to use a JavaScript framework like jQuery to handle the cross-browsers differences   A really basic example is   var xml     lt music gt  lt album gt Beethoven lt  album gt  lt  music gt     var result     xml  find  album   text      Note  As pointed out in comments  jQuery does not really do any XML parsing whatsoever  it relies on the DOM innerHTML method and will parse it like it would any HTML so be careful when using HTML element names in your XML  But I think it works fairly good for simple XML  parsing   but it s probably not suggested for intensive or  dynamic  XML parsing where you do not upfront what XML will come down and this tests if everything parses as expected

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lt script language  JavaScript  gt  function importXML         if  document implementation  amp  amp  document implementation createDocument                    xmlDoc   document implementation createDocument         null               xmlDoc onload   createTable            else if  window ActiveXObject                    xmlDoc   new ActiveXObject  Microsoft XMLDOM                xmlDoc onreadystatechange   function                          if  xmlDoc readyState    4  createTable                            else                   alert  Your browser can  t handle this script                return            xmlDoc load  emperors xml       function createTable         var theData         var x   xmlDoc getElementsByTagName  emperor        var newEl   document createElement  TABLE        newEl setAttribute  cellPadding  3       newEl setAttribute  cellSpacing  0       newEl setAttribute  border  1       var tmp   document createElement  TBODY        newEl appendChild tmp       var row   document createElement  TR        for  j 0 j lt x 0  childNodes length j                      if  x 0  childNodes j  nodeType    1  continue              var container   document createElement  TH                theData   document createTextNode x 0  childNodes j  nodeName               container appendChild theData               row appendChild container             tmp appendChild row       for  i 0 i lt x length i                      var row   document createElement  TR                for  j 0 j lt x i  childNodes length j                                      if  x i  childNodes j  nodeType    1  continue                      var container   document createElement  TD                        var theData   document createTextNode x i  childNodes j  firstChild nodeValue                       container appendChild theData                       row appendChild container                             tmp appendChild row             document getElementById  writeroot   appendChild newEl      lt  script gt   lt  HEAD gt    lt BODY onLoad  javascript importXML     gt   lt p id writeroot gt   lt  p gt   lt  BODY gt    For more info refer this http   www easycodingclub com xml-parser-in-javascript javascript-tutorials

[javascript] XML parsing of a variable string in JavaScript

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