document.write("<script>alert("+theinputvalue+")<script>");

var string="<script>alert("+theinputvalue+")<script>";document.write(string);

var canvas = document.getElementById("canvas"),
    ctx = canvas.getContext("2d")
for(var x=-100; x<100; x=x+.2){
    y = .1*(x*x)
    ctx.fillRect(x+50, -1*y+50, 2, 2);
}

eval('5*8-4')

// create an instance of math.js
var math = mathjs();

// evaluate an expression
math.eval('5*8-4'); // 36

// user defined function (returns a native JavaScript function)
var f = math.eval('f(x) = 2*x^2 + 6');

// use the function (for graphing or something)
f(2); // 14