running a script inside index.html with some conditions

Question

We have this script which we want to run only if user agent is ReactSnap. I tried doing this but it does not seem to be working.

<script>
     if(navigator.userAgent!=='ReactSnap'){
        <script src='//cdnt.netcoresmartech.com/smartechclient.js'</script>
     }
</script>

In this example you run this script if user agent is NOT ReactSnap. Probably your should use: `if(navigator.userAgent=='ReactSnap'){` — Roman Bush, Nov 19 '19 at 10:45

score 2 · Answer 1 · answered Nov 19 '19 at 10:50

The operator you are using in your conditional statement - !== is checking to see if the condition is not true. The correct syntax is if(navigator.userAgent=="ReactSnap") You are also trying to write html in a javascript context.

You should create your script tag using javascript, like the below example:

if(navigator.userAgent=="ReactSnap"){ // check userAgent
    var script = document.createElement("script"); // create a script tag
    script.setAttribute("type","text/javascript"); // set type to js
    script.setAttribute("src", "//cdnt.netcoresmartech.com/smartechclient.js") // define src for script tag
    document.head.appendChild(script); // load script into document head, or change this to a specific location
}

score 1 · Answer 2 · answered Nov 19 '19 at 11:06

This solution waits to add the script element to the page until we know the condition is true (tested in Chrome):

<body>

  <div>Page content goes here</div>

  <script>
    let conditionalScript = document.createElement("script");
    conditionalScript.innerHTML = "alert('woo!')";
    // (But set .src instead of .innerHTML)

    let userAgent = 'ReactSnap';
    if(userAgent == 'ReactSnap'){
      // (But check `navigator.userAgent` instead of `userAgent`)
      document.querySelector("body").appendChild(conditionalScript);
    }
  </script>

</body>

score 0 · Answer 3 · answered Nov 19 '19 at 10:53

I'd suggest using createElement, changing the source with setAttribute and appending it to the head like this.

if(navigator.userAgent!=='ReactSnap'){
  let smartTech = document.createElement('script');
  smartTech.setAttribute('src', '//cdnt.netcoresmartech.com/smartechclient.js');
  document.head.appendChild(smartTech);
}

score 0 · Answer 4 · answered Nov 19 '19 at 10:54

You can try something like this:

<script>
    if(navigator.userAgent=='ReactSnap'){
          var script = document.createElement('script');
          script.src = "//cdnt.netcoresmartech.com/smartechclient.js";
          document.head.appendChild(script);

    }
</script>

running a script inside index.html with some conditions

4 Answers4