why there is no pythonscript insine web browsers?

[Timuçin Kızılay]

I'm an old programmer coming from a cobol background and started to 
learn python. I'm using javasript for web based applications but after I 
started to learn python, the javascript language started to seem ugly to 
me. Now I'm wondering why there is java support on web browsers but no 
python support? there is even a vbscript support inside MS-IE but there 
is no python support. it would be really nice and easy for me to use 
python instead of javascript to write those ajax scripts.

Please tell me, is there a python substitude for JRE ?