Solved

Back Button Causing Issues With Hidden Divs

Posted on 2016-08-25
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Last Modified: 2016-08-31
On the page I have 2 hidden divs (display: none;) on page load. They are revealed with a jquery click function and then the user submits a form. If the browser back button is pressed, the divs are hidden again. I would like to have the divs shown on back button press, but I have no idea how to do this.
ScreenCast.flv
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Question by:seeraig
  • 3
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5 Comments
 
LVL 54

Accepted Solution

by:
Julian Hansen earned 500 total points
ID: 41771375
The reason they are not showing is that once you move off the page the state of the page is lost.

To preserve the state you would need to use a cookie or local storage to save a value that says whether or not the divs have been shown.
HTML
    <div class="hidden-div"> This is invisible on first read</div>
    <div class="hidden-div"> This is invisible on first read</div>
    <a href="#" class="show-divs">Show</a>

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jQuery
<script>
$(function() {
  var state = getState();
  if (state) {
    $('body').addClass('has-state');
  }
  
  $('.show-divs').click(function(e) {
    e.preventDefault();
    $('body').addClass('has-state');
    setState();
  });
});
function getState()
{
  var state;
  if (typeof Storage !== 'undefined') { // Localstorage
    state = localStorage.getItem('__state');
  }
  else { // Cookies
    state = getCookie('__state');
  }
  return state;
}

function setState()
{
  if (typeof Storage !== 'undefined') { // Localstorage
    localStorage.setItem('__state', '1');
  }
  else { // Cookies
    document.cookie = "__state=1";
  }
}

function getCookie(cookie) {
  var ret = false;
    var cookies = document.cookie;
  var pattern = cookie +'=(.*?);';
  var regex = new RegExp(pattern);
  var val = cookies.match(regex);
console.log(val);  
  if (val) ret = val[1];
  
    return ret;
}
</script>

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Working sample here
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LVL 54

Expert Comment

by:Julian Hansen
ID: 41771450
Updated code to selectively choose cookie / localstorage in sample
CSS
<style type="text/css">
.hidden-div {
  display: none;
}
body.has-state .hidden-div {
  display: block;
}
body.has-state .show-divs {
  display: none;
}
</style>

Open in new window

HTML
    <div>
      <button class="btn btn-danger" id="reset">Reset</button>
      <input type="radio" value="localstorage" id="localstorage" name="storage" checked/> Local Storage <input type="radio" value="cookie" name="storage" id="cookie"/> Cookie
	  <a href="#" class="show-divs btn btn-primary">Show</a>
    </div>
    <div class="hidden-div"> This is invisible on first read</div>
    <div class="hidden-div"> This is invisible on first read</div>

Open in new window

jQuery
<script>
$(function() {
  if (typeof Storage === 'undefined') {
  $('#localstorage').prop({checked: false, disabled: true});
  $('#cookie').prop('checked', true);
  }
  var state = getState();
  if (state) {
    $('body').addClass('has-state');
  }
  
  $('.show-divs').click(function(e) {
    e.preventDefault();
    $('body').addClass('has-state');
    var type = $('input[name="storage"]:checked').val();

    setState(type);
  });
  
  $('#reset').click(function(){
  if (typeof Storage !== 'undefined') {
    localStorage.clear();
  }
  document.cookie = "__state=; expires=0";
  location.reload();
  });
});
function getState()
{
  var state = false;
  if (typeof Storage !== 'undefined') { // Localstorage
    state = localStorage.getItem('__state');
  }
  
  if (!state) {
    state = getCookie('__state');
  }
  
  return state;
}

function setState(type)
{
  if (type == 'localstorage' && typeof Storage !== 'undefined') { // Localstorage
    localStorage.setItem('__state', '1');
  }
  else { // Cookies
    document.cookie = "__state=1";
  }
}

function getCookie(cookie) {
  var ret = false;
  var cookies = document.cookie;
  var pattern = cookie +'=(.*?);';
  var regex = new RegExp(pattern);
  var val = cookies.match(regex);
console.log(val);  
  if (val) ret = val[1];
  
    return ret;
}
</script>

Open in new window

Updated sample here
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Author Comment

by:seeraig
ID: 41771481
Thank Julian. I'll try and test this out later today and let you know if I can get it working.
0
 

Author Comment

by:seeraig
ID: 41774148
Hi Julian,

This seems like I got this working, need to test a little more. What's the best way to delete the cookie, like after checkout?
0
 
LVL 54

Expert Comment

by:Julian Hansen
ID: 41774342
Just set the cookie to a blank value with an expiry date in the past (-1, 0, 1970-01-01 etc)

You can read more on these links

https://developer.mozilla.org/en-US/docs/Web/API/Document/cookie#notes
http://www.w3schools.com/js/js_cookies.asp

I would recommend reading both of those pages through to get a complete understanding of how cookies work.
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