/* * Expand any templates at or beneath element e. * If any of the templates use XPath expressions with namespaces, pass * a prefix-to-URL mapping as the second argument as with XML.XPathExpression( ) * * If e is not supplied, document.body is used instead. A common * use case is to call this function with no arguments in response to an * onload event handler. This automatically expands all templates. */ XML.expandTemplates = function(e, namespaces) { // Fix up arguments a bit. if (!e) e = document.body; else if (typeof e == "string") e = document.getElementById(e); if (!namespaces) namespaces = null; // undefined does not work // An HTML element is a template if it has a "datasource" attribute. // Recursively find and expand all templates. Note that we don't // allow templates within templates. if (e.getAttribute("datasource")) { // If it is a template, expand it. XML.expandTemplate(e, namespaces); } else { // Otherwise, recurse on each of the children. We make a static // copy of the children first so that expanding a template doesn't // mess up our iteration. var kids = []; // To hold copy of child elements for(var i = 0; i < e.childNodes.length; i++) { var c = e.childNodes[i]; if (c.nodeType == 1) kids.push(e.childNodes[i]); } // Now recurse on each child element for(var i = 0; i < kids.length; i++) XML.expandTemplates(kids[i], namespaces); } }; /** * Expand a single specified template. * If the XPath expressions in the template use namespaces, the second * argument must specify a prefix-to-URL mapping */ XML.expandTemplate = function(template, namespaces) { if (typeof template=="string") template=document.getElementById(template); if (!namespaces) namespaces = null; // Undefined does not work // The first thing we need to know about a template is where the // data comes from. var datasource = template.getAttribute("datasource"); // If the datasource attribute begins with '#', it is the name of // an XML data island. Otherwise, it is the URL of an external XML file. var datadoc; if (datasource.charAt(0) == '#') // Get data island datadoc = XML.getDataIsland(datasource.substring(1)); else // Or load external document datadoc = XML.load(datasource); // Now figure out which nodes in the datasource will be used to // provide the data. If the template has a foreach attribute, // we use it as an XPath expression to get a list of nodes. Otherwise, // we use all child elements of the document element. var datanodes; var foreach = template.getAttribute("foreach"); if (foreach) datanodes = XML.getNodes(datadoc, foreach, namespaces); else { // If there is no "foreach" attribute, use the element // children of the documentElement datanodes = []; for(var c=datadoc.documentElement.firstChild; c!=null; c=c.nextSibling) if (c.nodeType == 1) datanodes.push(c); } // Remove the template element from its parent, // but remember the parent, and also the nextSibling of the template. var container = template.parentNode; var insertionPoint = template.nextSibling; template = container.removeChild(template); // For each element of the datanodes array, we'll insert a copy of // the template back into the container. Before doing this, though, we // expand any child in the copy that has a "data" attribute. for(var i = 0; i < datanodes.length; i++) { var copy = template.cloneNode(true); // Copy template expand(copy, datanodes[i], namespaces); // Expand copy container.insertBefore(copy, insertionPoint); // Insert copy } // This nested function finds any child elements of e that have a data // attribute. It treats that attribute as an XPath expression and // evaluates it in the context of datanode. It takes the text value of // the XPath result and makes it the content of the HTML node being // expanded. All other content is deleted. function expand(e, datanode, namespaces) { for(var c = e.firstChild; c != null; c = c.nextSibling) { if (c.nodeType != 1) continue; // elements only var dataexpr = c.getAttribute("data"); if (dataexpr) { // Evaluate XPath expression in context. var n = XML.getNode(datanode, dataexpr, namespaces); // Delete any content of the element c.innerHTML = ""; // And insert the text content of the XPath result c.appendChild(document.createTextNode(getText(n))); } // If we don't expand the element, recurse on it. else expand(c, datanode, namespaces); } } // This nested function extracts the text from a DOM node, recursing // if necessary. function getText(n) { switch(n.nodeType) { case 1: /* element */ var s = ""; for(var c = n.firstChild; c != null; c = c.nextSibling) s += getText(c); return s; case 2: /* attribute*/ case 3: /* text */ case 4: /* cdata */ return n.nodeValue; default: return ""; } } };
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