使用 javascript 根据推荐人 URL 更改 IMG SRC

Change IMG SRC based on referrer URL using javascript

我不是最擅长这方面的,但我想知道是否有一种方法可以使用 javascript 根据引用 URL 更改图像 src。我把它拼凑在一起,但它不起作用,我不确定为什么。谢谢

<script>
  var ref = document.refferer;
   if(ref.includes("dev.mastercoolproducts.com")){
     $(document).ready(function() {
  $("#fc-logo").attr("src","https://essickair.foxycart.com/cache?url=https://www.dropboxusercontent.com/s/uhy2eoxjojeqwsj/mc-logo.png?dl=0");
       });
   }else{
     $(document).ready(function() {
    $("#fc-logo").attr("src","https://essickair.foxycart.com/cache?url=https://dl.dropboxusercontent.com/s/q635dlso4f8pdol/ac-color.png?dl=0");
       });
     }
</script>

看来您可能 运行在文档初始化之前就已经使用了这段代码。您只想 运行 代码来检查您的文档是否被初始化一次。我修改了您的代码,认为这应该可以解决问题:

//Only run once the document is ready
$(document).ready(function() {
  // this sets the value to '' if refferrer is somehow empty
  var ref = document.refferer || '';
  // since you'll be searching for this node multiple times, just store it in a variable:
  var logoImg = $("#fc-logo");
  if (ref.includes("dev.mastercoolproducts.com")) {
    logoImg.attr("src", "https://essickair.foxycart.com/cache?url=https://www.dropboxusercontent.com/s/uhy2eoxjojeqwsj/mc-logo.png?dl=0");
  } else {
    logoImg.attr("src", "https://essickair.foxycart.com/cache?url=https://dl.dropboxusercontent.com/s/q635dlso4f8pdol/ac-color.png?dl=0");
  }
})