Help please with using a variable from url in function

JavaScript
1

Can someone please tell me how I would modify the following function to get it to check if a url variable is present and if so to add it into the string variable for the url.

function ajaxFunction(pagenum){
	var ajaxRequest;  // The variable that makes Ajax possible!
	
	try{
		// Opera 8.0+, Firefox, Safari
		ajaxRequest = new XMLHttpRequest();
	} catch (e){
		// Internet Explorer Browsers
		try{
			ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try{
				ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e){
				// Something went wrong
				alert("Your browser broke!");
				return false;
			}
		}
	}
	// Create a function that will receive data sent from the server
	ajaxRequest.onreadystatechange = function(){
		if(ajaxRequest.readyState == 4){
			var ajaxDisplay = document.getElementById('ajaxDiv');
			ajaxDisplay.innerHTML = ajaxRequest.responseText;
		}
	}
	var drop_1 = document.getElementById('drop_1').value;
	var model = document.getElementById('model').value;
	var mileage = document.getElementById('mileage').value;
	var colour = document.getElementById('colour').value;
	var age = document.getElementById('age').value;
	var min_price = document.getElementById('min_price').value;
	var max_price = document.getElementById('max_price').value;
	var min_engine_size = document.getElementById('min_engine_size').value;
	var max_engine_size = document.getElementById('max_engine_size').value;
	//var pics = document.getElementById('pics').value;
	if (document.getElementById("pics").checked==true) {
		var photos = "Yes";
	}
	else {
		var photos = "No";
	}
	var keywords = document.getElementById('keywords').value;
	var queryString = "?drop_1=" + drop_1 + "&model=" + model + "&mileage=" + mileage + "&colour=" + colour + "&age=" + age + "&min_price=" + min_price + "&max_price=" + max_price + "&min_engine_size=" + min_engine_size + "&max_engine_size=" + max_engine_size + "&photos=" + photos + "&keywords=" + keywords + "&page=" + pagenum;
	ajaxRequest.open("GET", "filtered.php" + queryString, true);
	ajaxRequest.send(null); 
}

If my url is index.php?make=Apolo then I need to get this added into the var queryString part of the function so that the ajax returns the correct values.

any help would be greatly appreciated.

Thanks in advance.

2

location.search will give you the querystring for the current page. It does have the question mark at the start though, so you may want to get only what comes after that, by using .substring(1)