Dan_net,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
.changeColor.red{fill:none;stroke:#FF0000;stroke-width:5;stroke-miterlimit:10;}
.changeColor.blue{fill:none;stroke:#0000FF;stroke-width:5;stroke-miterlimit:10;}
.changeColor.green{fill:none;stroke:#008000;stroke-width:5;stroke-miterlimit:10;}
.changeColor {fill:none;stroke:#FFFF00;stroke-width:5;stroke-miterlimit:10;}
.st1 {fill:none;stroke:#ccccc;stroke-width:5;stroke-miterlimit:10;}
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script>
$(window).on('load', function () {
var svgobject = document.getElementById('imap');
$('#changeColor input[type=button]').click(function (e) {
var row = $(this).parent();
var className = row.attr("id");
var idClicked = e.target.id;
$("."+className, svgobject).removeClass("red blue green").addClass(idClicked);
});
});
</script>
</head>
<body>
<div id="changeColor">
<input type="button" id="red" value="Red">
<input type="button" id="blue" value="Blue">
<input type="button" id="green" value="Green">
</div>
<svg id="imap" version="1.1" xmlns="http://www.w3.org/2000/svg" x="0" y="0" viewBox="0 0 500 500" xml:space="preserve"><metadata><x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="Adobe XMP Core 5.6-c067 79.157747, 2015/03/30-23:40:42 "><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><rdf:Description rdf:about=""/></rdf:RDF></x:xmpmeta></metadata>
<polyline class="changeColor " points="132 47.5 365 47.5 481.5 249 365.1 450.5 132 450.5 15.7 249 107.9 89.5 338 89.5 429.4 248 338.1 406.5 155 406.5 64.2 248 133.6 127.5 319 127.5 388.2 249 318.5 370.5 179 370.5 109.3 249 160.1 160.5 300 160.5 350.8 249 299.8 337.5 198 337.5 146.8 249 181.5 188.7 282 188.1 "/>
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</body>
</html>