setting variable with query strings

We can send information to another page thru the use of a query string. It goes on the end of the URL when we give the href to a link:

<a href="nextPage.htm[color red]?some variable=value[/color]>"
The ? sign indicates the start of the query string
we can have as many variable/value pairs as we like, we separate them using the & sign:

...[color red]?someVariable=value&someOther=value2...[/color]

When the next page is loaded the query string is stored for us at [color red] location.search [/color].When it arrives the one above would look like this:

[color red]?someVariable=value&someOther=value2[/color]

which is one big string,
now we have to slice it up so we can use it. You can do many things, you could store them in a matrix, or just set the variables using eval (simpler).
[color red]
function getQuery(){
var queryString = location.search;

-- get rid of ? at start --
var data = queryString.slice(1,data_pre.length);


-- Splits the string at the & and returns an array containing the parts, variable=value pairs.Stored as single string. --

dataArray = data.split("&");

-- Here is where you could take each element of the dataArray and split at the = sign, and store the variable values separately. I am just going to set the variables. --

for (j=0;j<dataArray.length;j++){
eval(dataArray[j])
}

}
[/color]

So the first entry for our dataArray looked like:
someVariable=value

using eval(someVariable=value) sets the variable with it's value.

While sometimes these techniques are useful - a middleware solution is far les time consuming to set up. Server-Side pre-processors like ASP,PHP,PERL etc are ideally suited to this kind if job, and have pre defined methods making all of this unnecessary.