Access to DOM using node.js
i want to access to html file and get an element by id using node.js, this is my html file :
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Diagram </title>
<script>
function generatePNG (oViewer) {
// some other code
reader.onloadend = function() {
base64data = reader.result;
var image = document.createElement('img');
image.setAttribute("id", "GraphImage");
image.src = base64data;
document.body.appendChild(image);
}
}, "image/png", oImageOptions);
return sResult;
var sResult = generatePNG (oEditor.viewer);
});
</script>
</head>
<body >
<div id="diagramContainer"></div>
</body>
</html>
I want to do get document.getElementById("GraphImage").src but with node.js.
I've found that I can use cheerio or jsdom to acces the DOM with node.js, so I've tried this code with cheerio:
var cheerio = require('cheerio'),
$ = cheerio.load('file.html');
But I didn't founnd the instruction that allow me to get the image.src from the html file, like this instruction: document.getElementById("GraphImage").src
Answer
cheerio.load() accepts a string as the argument. By setting: cheerio.load('file.html') cheerio will try to implement DOM from the string file.html. Obviously, that is not what you want.
You should get the html data from your file first, then pass it to the cheerio. Also as @Quentin metioned, cheerio is a cut down implementation of jQuery, so you should use jQuery selectors to get a ceratin element. For your particular case it would be: $("#GraphImage"). Here is how your code should look like:
var cheerio = require('cheerio'),
$ = cheerio.load('file.html'),
fs = require('fs');
fs.readFile('./index.html', function (err, html) {
if (err) {
throw err;
} else {
$ = cheerio.load(html.toString());
console.log($('#GraphImage').attr('src'));
}
EDIT:
Also, in the html file that you have provided, you are appending some objects to the DOM with the help of javascript. If you want to access them on the server, the javascript should be interpreted there. You can use something like phantomjs to achieve it, but things get much more complicated.