function setInput(obj, default_txt) {
    if(obj.value == "") {
        obj.value = default_txt;
    } else {
        if(obj.value == default_txt){
            obj.value = "";
        }
    }
}

function clearInput(obj, default_txt) {
    if(obj.value == default_txt){
        obj.value = "";
    }

}

function resetInput(obj, default_txt) {
    if(obj.value == "") {
        obj.value = default_txt;
    } 
}

function clearJSFields()
{
	if (document.getElementById("q").value != "") setInput(document.getElementById("q"), "ex. : vente, ingénieur, Linux...");
	if (document.getElementById("where").value != "") setInput(document.getElementById("where"), "ex. : Bruxelles, ou 1000");
}