May 30, 2020

JavaScript implements a method that controls the opening of a file save as dialog

The example in this article describes how JavaScript implements the control of opening file save as dialog box. Share with you for your reference. The details are as follows:

Here, JS opens the image save as dialog box to prompt the user to save the file

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<script src="js/jquery.min.js" type="text/javascript"></script>
<script language="JavaScript">
<!--
function downLoadImage(imagePathURL){
// If the middle IFRAME Does not exist, adds
if(!document.getElementById("_SAVEASIMAGE_TEMP_FRAME"))
jQuery('<iframe style="display:none;" id="_SAVEASIMAGE_TEMP_FRAME"
name="_SAVEASIMAGE_TEMP_FRAME" onload="_doSaveAsImage();"
width="0" height="0" src="about:blank"></iframe>').appendTo("body");
if(document.all._SAVEASIMAGE_TEMP_FRAME.src!=imagePathURL){
// The image address has changed. Load the image
document.all._SAVEASIMAGE_TEMP_FRAME.src = imagePathURL;
}else{
// The image address does not change, save as directly
_doSaveAsImage();
}
}
function _doSaveAsImage(){
if(document.all._SAVEASIMAGE_TEMP_FRAME.src!="about:blank")
document.frames("_SAVEASIMAGE_TEMP_FRAME").document.execCommand("SaveAs");
}
//-->
</script>
</head>
<body>
<input type="button" value="download image"
onclick="downLoadImage('https://www.ofstack.com/images/logo.gif');">
</body>
</html>

I hope this article is helpful for you to design javascript program.