DOM attributes for SVG Doesnt work, why? And how to fix it?

Question

Assuming that
<rect x="0" y="0" .../> exists inside <svg>.
And <textarea> and <button onclick = "submit;"> too.
... means other attributes
The js code:
function submit(){
var p = document.getElementById("player");
var input = document.getElementById("input").value;
var py = p.top.toString().replace("px", '');
var px = p.left.toString().replace("px", '');
console.log("px = "+px+"; py = "+py)
for(var node in input){
var node = input[node];
if (node == ">"){
p.left = parseInt(px) + parseInt("250");
console.log(p.x);
}
}
}
Assuming this code above would word somehow. And it made an error, just giving me [SVGAnimationLength].
Why? And how to fix it?

Answer 1

// see my code for move elements inside SVG
https://code.sololearn.com/WBlYiLMrR7xY/#html

Answer 2

Please show all the code!