Question

i want to implement this animation below:

and i’m create js fiddle to work like that, but i have stack when i want to set a position of (x,y) ..

var interval;
function moveit(left,top) {
    $("#obj").css("left",left+'px');
    $("#obj").css("top",top+'px');
}
$("#change").click(function(){
    var left = $("#left").val(); //posisi x
    var top = $("#top").val();  //posisi y
    var velocity= 1;

    interval = setInterval(function() {
        left = parseFloat(left) + parseFloat(velocity);
        top = parseFloat(top) + parseFloat(velocity);
        console.log('position x = ' + left);
        console.log('position y = ' + top);

        if(top >= 400 ) {
        clearInterval(interval);
        }

        moveit(left,top);
    },10);
});

$("#clear").click(function(){
clearInterval(interval);
});
​

this is my js fiddle http://jsfiddle.net/viyancs/MxuRP/1/

my question

1. how to getting x,y coordinate of that curve by generating code ?
2. maybe you have another idea for make this better?

thanks you

Answer 1

Change the y-component of the velocity through time.

http://jsfiddle.net/MxuRP/2/

var interval;
function moveit(left,top) {
    $("#obj").css("left",left+'px');
    $("#obj").css("top",top+'px');
}
$("#change").click(function(){
    var left = $("#left").val(); //posisi x
    var top = $("#top").val();  //posisi y
    var velocityX = 1;
    var velocityY = 0;
    var accelerationY = 0.1;

    interval = setInterval(function() {
        left = parseFloat(left) + parseFloat(velocityX);
        velocityY += accelerationY;
        top = parseFloat(top) + parseFloat(velocityY);
        console.log('position x = ' + left);
        console.log('position y = ' + top);

        if(top >= 400 ) {
        clearInterval(interval);
        }

        moveit(left,top);
    },10);
});

$("#clear").click(function(){
clearInterval(interval);
});