jQuery animate（）一旦停止

Question

Im trying to make a box animate when i scroll down to its position, but the animation wont stop, the element just keeps repeating the animation forever. The code im using :

jQuery(document).scroll(function (e) {
    var value = jQuery(this).scrollTop();
    if (value = 600) {

        jQuery( "body" ).addClass( "scroll" );
        jQuery('#car1').animate({top: '+=50px'}, 2000);
     }




    });

Answer 1

A single = isnt a comparison operator. It is in fact assigning a value to your variable.

That being said, your condition :

 if (value = 600)

is always true since 600 is a truthy value.

Try using == or === .

To anime once, you can use the class you are inputing on the body. Just invert your 2 lines and do a condition :

if(!jQuery("body").hasClass("scroll")) //Animate only if it haven't the class scroll
     jQuery('#car1').animate({top: '+=50px'}, 2000);
jQuery( "body" ).addClass( "scroll" );