The second parameter should be name..Something like windowname

<input type="button" value="new win" 
onclick="window.open('http://yahoo.com','windowname', 'width=500, height=400')"  />

Just had this exact same issue. Just in case you wanted the code that fixed it. I used this:

newWindow = window.open("", "_blank");

request = $.ajax({ ... my request which returns a url to load ... })

request.done((function(_this) {
        return function(data, textStatus, jqXHR) {
          return newWindow.location = data.Url;
        };
      })(this));

You can use window.open("<%=forHyperLink%>",'name_'+(new Date()).getTime(),'height=600,width=800');

'name_'+(new Date()).getTime() will be changed at each window opened

oNewWindow = window.open( [sURL] [, sName] [, sFeatures] [, bReplace])

Please find the detail of window.open from the following link

http://msdn.microsoft.com/en-us/library/ms536651(v=vs.85).aspx

Hello John M_043,

Thank you for your positive response, as the design issue has caused you a bad experience.

You can go to Feedback Hub to give feedback on this issue.

If there is anything not clear, please do not hesitate to let me know.

 Best Regards,

 Lenka-MSFT| Microsoft Community Support Specialist

Hi JDSuser, welcome to the Microsoft community, my name is Bruno Leonel.

We will be happy to help and see if we can resolve this issue for you. Follow some of the recommended suggestions below that have helped others.

I understand that you are having problems opening links in a new tab and I will try to help you in the best way.

There are some possibilities to open a link in the same tab see below:

In Microsoft Edge, you can open a link in a new tab, just right-click on the link and then choose “Open in a new tab”

You can also use the Ctrl key (press it and keep it pressed) and click with the left mouse button and the link will open in a new tab.

NOTE: If the links that are opening in a new window are from the google search site

At the bottom of the page click settings -> search settings

And confirm that the following option is checked: "Open each selected result in a new browser window"

Give it a try, if it doesn't work, check the steps below:

To try to resolve it, follow the steps below:

step 1

With Microsoft Edge open press Alt+F;

Click "Settings" / "Reset Settings" / "Restore Settings to Default Values";

And confirm by clicking Reset;

Close the browser and open it again.

After this process, check if you are in agreement.

Step 2

Note: If when opening Microsoft Edge, a Welcome tab opens, it means that the browser has been reset. Make a backup of your bookmarks before performing this action.

Close Microsoft Edge.

Open the start menu and type PowerShell.

Right-click Run As Administrator.

Copy and paste the command below:

Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "C:\Windows\SystemApps\*Edge*\AppXManifest.xml"}
$manifest = (Get-AppxPackage *Edge*).InstallLocation + '\AppxManifest.xml' ; Add-AppxPackage -DisableDevelopmentMode -Register $manifest

After the command execution is complete, try to open Microsoft Edge.

If the answer helped in any way, please mark it as an answer, if your question has not been solved, please post again.

I hope I helped, see you later!