轉到頁面時顯示警告框一次

Question

我在這裏有一個代碼，每次頁面重新載入警報時都會彈出。但我希望警報框彈出一次。例如，無論何時打開該頁面，都會彈出警報，但如果我重新加載該頁面，將不會彈出警告框。任何人都知道我該怎麼做？

這裏是我的警告框代碼：

<script type="text/javascript"> 
    window.onload = function() { 
    alert("Sending of SMS is scheduled TODAY!"); 
    //dom not only ready, but everything is loaded 
    } 
</script> 

感謝提前的幫助。

Answer 1

做如下：

<script type="text/javascript"> 
    var dateObj = new Date(); 
    var month = dateObj.getUTCMonth() + 1; //months from 1-12 
    var day = dateObj.getUTCDate(); 
    var year = dateObj.getUTCFullYear(); 
    var today = year + "/" + month + "/" + day; 
    window.onload = function() { 
      var item = localStorage.getItem("alertShown_"+today); 
      if (item === null || item != "Yes") { 
      //check if localStorage has value or it is == "Yes" 
       alert("Sending of SMS is scheduled TODAY!"); 
       localStorage.setItem("alertShown_"+today,"Yes"); //set some value for future check 
      } 
    } 
</script>