Serialize name/value pairs

I have an array of objects that each have a name/value property. The array can contain multiple objects with the same name property. I want to serialize this array into the form:

name:value,value|name:value|name:value,value,value

So basically each property is separated by a | and each value by a ,. The above example is not exactly how I want it to look, just an example of the syntax, results will vary based upon input.

Here is an example of the array:

var objs = [
    {name:"name1", value: "value1"}, 
    {name:"name4", value: "value4"},
    {name:"name3", value: "value3"},
    {name:"name2", value: "value2"},
    {name:"name2", value: "value2"},
    {name:"name2", value: "value3"}
];

I wrote some code to perform this serialization, but I wanted to see if anyone could suggest improvements to this code, I know there are some Javascript experts on this site and wanted to get their opinion:

function serialize(objs){
    var out = "";
    for(var i = 0; i < objs.length; i++){
        var propKey = objs[i].name + ":";

        if (out.indexOf(propKey) == -1){
            out += "|" + propKey; 
        }

        var position = out.indexOf(propKey) + propKey.length;
        out = out.substring(0, position) + objs[i].value + "," + out.substring(position);
    }
    return out.substring(1,out.length-1).replace(/\,\|/g,"|");
}

JS Fiddle: http://jsfiddle.net/BHsuM/

BTW jQuery is acceptable.