<script>
function Fun()
{
alert("abcd");
}var a = Fun;
var b=a.toString().match(/\b(\w+)\(\)/g)
alert(b[0].replace(/\(\)/,''))
</script>
function Fun()
{
alert("abcd");
}var a = Fun;
var b=a.toString().match(/\b(\w+)\(\)/g)
alert(b[0].replace(/\(\)/,''))
</script>
{
alert("abcd");
}var a = Fun;var ss=""
a.toString().replace(/function\s+(\S+)\s*\(/gi,function($0,$1){ss=$1});
alert(ss);
<script>
function Fun()
{
alert("abcd");
}var a = Fun;var ss=a.toString().match(/^function\s+(\S+)\s*\(/)[1];
alert(ss);</script>