#DOMHandler2

The DOM handler (formally known as DefaultHandler) creates a tree containing all nodes of a page. The tree may be manipulated using the DOMUtils library.

###Why domhandler2? I needed an easy way to transform and modify the attributes of html tags. See attribTransforms option below. If you want the original, it's here original domhandler

##Usage

var handler = new DomHandler([ <func> callback(err, dom), ] [ <obj> options ]);
// var parser = new Parser(handler[, options]);

##Example

var htmlparser = require("htmlparser2");
var rawHtml = "Xyz <script language= javascript>var foo = '<<bar>>';< /  script><!--<!-- Waah! -- -->";
var handler = new htmlparser.DomHandler(function (error, dom) {
    if (error)
    	[...do something for errors...]
    else
    	[...parsing done, do something...]
        console.log(dom);
});
var parser = new htmlparser.Parser(handler);
parser.write(rawHtml);
parser.done();

Output:

[{
    data: 'Xyz ',
    type: 'text'
}, {
    type: 'script',
    name: 'script',
    attribs: {
    	language: 'javascript'
    },
    children: [{
    	data: 'var foo = \'<bar>\';<',
    	type: 'text'
    }]
}, {
    data: '<!-- Waah! -- ',
    type: 'comment'
}]

##Option: normalizeWhitespace Indicates whether the whitespace in text nodes should be normalized (= all whitespace should be replaced with single spaces). The default value is "false".

The following HTML will be used:

<font>
	<br>this is the text
<font>

###Example: true

[{
    type: 'tag',
    name: 'font',
    children: [{
    	data: ' ',
    	type: 'text'
    }, {
    	type: 'tag',
    	name: 'br'
    }, {
    	data: 'this is the text ',
    	type: 'text'
    }, {
    	type: 'tag',
    	name: 'font'
    }]
}]

###Example: false

[{
    type: 'tag',
    name: 'font',
    children: [{
    	data: '\n\t',
    	type: 'text'
    }, {
    	type: 'tag',
    	name: 'br'
    }, {
    	data: 'this is the text\n',
    	type: 'text'
    }, {
    	type: 'tag',
    	name: 'font'
    }]
}]

##Option: withStartIndices Indicates whether a startIndex property will be added to nodes. When the parser is used in a non-streaming fashion, startIndex is an integer indicating the position of the start of the node in the document. The default value is "false".

##Option: attribTransforms An object that allows you to transform and modify attributes for tags. The property keys for this object should map to valid html tags. Each property should map to a function that receives an attribs object. You can do whatever you want to the attribs, but once you're done, make sure you return them or they'll be null! The example below transforms relative urls paths of img tags into absolute paths.

var htmlparser = require('htmlparser2');
var DomHandler = require('domhandler2');
var tohtml = require('htmlparser-to-html');
var url = require('url');

var html = '<a href="/NUlzFcY.gif"><img src="/NUlzFcY.gif"></a>';
var handler = function(domErr, dom) {
  if (domErr) {
    throw domErr;
  } else {
    html = tohtml(dom);
  }
};

var attribTransforms = {
  'img': function(attribs) {
    if (attribs.src) {
      // this allows you to transform relative paths into absolute paths
      attribs.src = url.resolve('http://i.imgur.com', attribs.src);
    }

    // remember to return the attribs or they will be null!
    return attribs;
  },
  'a': function(attribs) {
    if (attribs.href) {
      attribs.href = url.resolve('http://i.imgur.com', attribs.href);
    }

    return attribs;
  }
};

var domHandler = new DomHandler(handler, {attribTransforms: attribTransforms});

var parser = new htmlparser.Parser(domHandler);
parser.write(html);
parser.done();
console.log(html);