Is there a simple way to have a local webpage display a variable passed in the URL? - html

Question

I am experimenting with a Firefox extension that will load an arbitrary URL (only via HTTP or HTTPS) when certain conditions are met.
With certain conditions, I just want to display a message instead of requesting a URL from the internet.
I was thinking about simply hosting a local webpage that would display the message. The catch is that the message needs to include a variable.
Is there a simple way to craft a local web page so that it can display a variable passed to it in the URL? I would prefer to just use HTML and CSS, but adding a little inline javascript would be okay if absolutely needed.
As a simple example, when the extension calls something like:
folder/messageoutput.html?t=Text%20to%20display
I would like to see:
Message: Text to display
shown in the browser's viewport.

Answer 1

You can use the "search" property of the Location object to extract the variables from the end of your URL:
var a = window.location.search;
In your example, a will equal "?t=Text%20to%20display".
Next, you will want to strip the leading question mark from the beginning of the string. The if statement is just in case the browser doesn't include it in the search property:
var s = a.substr(0, 1);
if(s == "?"){s = substr(1);}
Just in case you get a URL with more than one variable, you may want to split the query string at ampersands to produce an array of name-value pair strings:
var R = s.split("&");
Next, split the name-value pair strings at the equal sign to separate the name from the value. Store the name as the key to an array, and the value as the array value corresponding to the key:
var L = R.length;
var NVP = new Array();
var temp = new Array();
for(var i = 0; i < L; i++){
temp = R[i].split("=");
NVP[temp[0]] = temp[1];
}
Almost done. Get the value with the name "t":
var t = NVP['t'];
Last, insert the variable text into the document. A simple example (that will need to be tweaked to match your document structure) is:
var containingDiv = document.getElementById("divToShowMessage");
var tn = document.createTextNode(t);
containingDiv.appendChild(tn);

Answer 2

getArg('t');
function getArg(param) {
var vars = {};
window.location.href.replace( location.hash, '' ).replace(
/[?&]+([^=&]+)=?([^&]*)?/gi, // regexp
function( m, key, value ) { // callback
vars[key] = value !== undefined ? value : '';
}
);
if ( param ) {
return vars[param] ? vars[param] : null;
}
return vars;
}