var keyPress = 0;
var curElem = 0;

document.onkeypress  = function(e) {
    keyPress = (e)?e.which:event.keyCode
}

function RunClick(x) {
    if( keyPress == "13" ) {
        curElem = x;
        GoClick();
    }
    return false;
}

function GoClick() {
    //alert( curElem.id );
    var textbox = document.getElementById(curElem);
    window.location = "/Meta/Pages/Zoeken.aspx?keyword=" + textbox.value;
}