滚动发送ajax请求

Question

I want to send ajax request when my page is first time scrolled to 20% of the actual height of the page .I have tried this but this is not working .

$(window).scroll(function(){
    if ($(window).scrollTop() >= ($(document).height() - $(window).height())*0.2){
        sendajax();
    }
});

Please suggest me what i have done wrong.I have to send only first time when scrolled to 20%

Answer 1

Problem is you are calling sendajax() on $(window).scroll(function().

So every time you scrolled page it will check your condition in that block. After 20% your condition if ($(window).scrollTop() >= ($(document).height() - $(window).height())*0.2) always gone be true so it will call sendajax() every time you scroll page (after 20%).

probable solution is you may set flag inside condition block like

var isAjaxCalled= false; 
$(window).scroll(function(){
if (($(window).scrollTop() >= ($(document).height() - $(window).height())*0.2) && !isAjaxCalled){
isAjaxCalled= true; 
    sendajax();
}
});

This may helps you.

thanks