用javascript控制svg的图片颜色

SVG：(1.svg)

<?xml version="1.0" standalone="no"?> 
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"> 
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="100%" height="100%" > 
<circle cx="100" cy="100" r="40" fill="#FFFFFF" id="aaa0"/> 
<circle cx="200" cy="100" r="40" fill="#FFFFFF" id="aaa1"/> 

<circle cx="100" cy="200" r="40" fill="#FFFFFF" id="aaa2"/> 
<circle cx="200" cy="200" r="40" fill="#FFFFFF" id="aaa3"/> 
</svg> 

HTML:(1.htm)

<script type="text/javascript">
function member(id, color) {
    this.id = id;
    this.color = color;
}
var big_table = new Array();
big_table[0] = new member("aaa0","#FF0000");
big_table[1] = new member("aaa1","#99FF00");
big_table[2] = new member("aaa2","#0000FF");
big_table[3] = new member("aaa3","#9900FF");

function color_map_init() {
    var map = document.getElementById('map');
    var svg_document = map.contentDocument;
    for (var iii in big_table) {
        obj = big_table[iii].id;
        this_color = big_table[iii].color;
        this_obj = svg_document.getElementById(obj);
        this_obj.setAttribute("style", "fill:" + this_color);
    }
}

function color_map(iii,new_color) {
    var map = document.getElementById('map');
    var svg_document = map.contentDocument;
    //this_obj = svg_document.getElementById("a1");//objstr
    obj = big_table[iii];
    this_obj = svg_document.getElementById(obj.id);
    this_obj.setAttribute("style", "fill:" + new_color);
}
</script>
<input type="button" value="初始化init" onclick="color_map_init();">
<input type="button" value="按钮1" onclick="color_map(0,'#FFFF00');">
<input type="button" value="按钮2" onclick="color_map(1,'#FFFF00');">
<input type="button" value="按钮3" onclick="color_map(2,'#FFFF00');">
<input type="button" value="按钮4" onclick="color_map(3,'#FFFF00');">

<div style="position:absolute;left:0px; top:60px;border:solid 1px;">
<object id="map" type="image/svg+xml" data="1.svg" width="800" height="700"></object>
</div>