Safari中的window.onerror(Javascript)

但我需要使用它.请给我正确的方法.

<script language="javascript" type="text/javascript">
window.onerror = function(msg,url,line)
{
    document.write("Message\t = "+msg + "<br/>Location\t = " + url + "<br/>Line No.\t = " + line + "<br/>Error No.\t = " + this.err.number);
}
this.err = Error(12,"My Own Error");
throw this.err;
</script>

==========================================
Internet Explorer:

My Error
Message = My Own Error
Location = http://localhost/practice/JavaScript/window.errors.PHP
Line No. = 8
Error No. = 12 
================================================
Mozilla FireFox:

My Error
Message = Script error.
Location = My Own Error
Line No. = 0
Error No. = undefined 
=====================================================
Safari,Chrome,Opera:

My Error

看看代码Mozilla提供的错误信息.我所做的？