guia3.js

window.onload = function(){
    let canvas = document.getElementById("tehLostCanvas");
    if(canvas && canvas.getContext){
       let ctx = canvas.getContext("2d");
        if(ctx){

            ctx.lineaWidth = 15;
            ctx.strokeStyle = "yellow";
            ctx.fillStyle = "red";

            ctx.beginPath();
            ctx.moveTo(50,100);
            ctx.lineTo(100,50);
            ctx.lineTo(150,100);
            ctx.lineTo(100,150);
            //ctx.fill();
            ctx.stroke();
            
            //sengunda linea
           
            ctx.moveTo(200,100);
            ctx.lineTo(250,50);
            ctx.lineTo(300,100);
            ctx.lineTo(250,150);
            ctx.closePath();
            ctx.stoke();


        }

    }else{
        alert("su navegador no soporta canvas");
    }
}