Question

我希望下面的代码只在网站首次加载时执行一次。我尝试使用cookies和sessionstorage。但我从未找到合适的解决方案。也许这是错的。有没有人知道如何用会话存储解决这个问题？我从来没有做过任何事情。也许是这样的？：

 if (!sessionStorage.alreadyClicked) {
    $('#my_div');
    sessionStorage.alreadyClicked = 1;
}

任何帮助将不胜感激。谢谢。

＆＃13;

var my_div;
topIgnore = 100;  // (in pixel units) used for function ignoreTop

window.onload = function() {
  my_div = document.getElementById('my_div');
  var my_div_style = window.getComputedStyle(my_div);
  var width_div = parseInt(my_div_style.width, 10);  // remove 'px' from string
  var height_div = parseInt(my_div_style.height, 10);
  // make sure the property exists, else you can get a NaN
  my_div.style.left = 0;
  my_div.style.top = 0;
  // event
  window.onmousemove = function(e) {
    // my_div.innerHTML = e.pageX +' - '+ (leftBorder + width_div) +' - '+ width_div;
    cursorIsInsideDiv(e);
  }
  // TO DO: feel free to make similar functions for left/right/bottom
  // removes the first 100px
  function ignoreTop(top) {
    if(top < topIgnore) {
      return topIgnore;
    }
    return top;
  }
  function cursorIsInsideDiv(e) {
    var leftBorder = parseInt(my_div.style.left, 10); // remove 'px' from string
    var topBorder  = parseInt(my_div.style.top, 10);  
    // move left 
    if( e.pageX <  leftBorder ) {
      my_div.style.left = e.pageX + 'px';
    }
    // move right
    else if( e.pageX >  (leftBorder + width_div)) {
      my_div.style.left = (e.pageX - width_div ) + 'px';
    }
    // move up 
    if( e.pageY <  topBorder ) {
      var top = e.pageY ;
      top = ignoreTop(top);
      my_div.style.top = top + 'px';
    }
    // move down
    else if( e.pageY >  (topBorder + height_div)) {
      my_div.style.top = (e.pageY - height_div ) + 'px';
    }
  }
}

＆＃13;

#my_div {
  width: 100%;
  height: 100%;
  padding: 0;
  margin: 0;
}
#my_div {
  width: 300px;
  height: 150px;
  background: #ff0000;
  position: absolute;
}

＆＃13;

<div id="my_div">
  <h2>Newsletter</h2>
  Name: <input type="text" name="fullname"><br>
  Email: <input type="text" name="email"><br>
</div>

＆＃13;

Answer 1

使用JS设置cookie：

document.cookie = "alreadyClicked=1; expires=Fri, 13 Jan 2017 20:00:00 UTC";

然后，你可以通过定义一个函数来检查它是否存在以找到值（来自http://www.w3schools.com/js/js_cookies.asp）：

function getCookie(cname) {
    var name = cname + "=";
    var decodedCookie = decodeURIComponent(document.cookie);
    var ca = decodedCookie.split(';');
    for(var i = 0; i <ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0) == ' ') {
            c = c.substring(1);
        }
        if (c.indexOf(name) == 0) {
            return c.substring(name.length, c.length);
        }
    }
    return "";
}
if (getCookie("alreadyClicked") == "1") {
    // do stuff if already clicked
} else {
    // prompt for click?
}

Answer 2

我刚刚插入了代码。有效。纠正了这是否错误。

 if (!sessionStorage.alreadyClicked) {
$('#my_div');
sessionStorage.alreadyClicked = 1;

}

Javascript - 每个会话运行一次

2 个答案: