enc.html

<p>URI encode</p>

<p>
<textarea rows="10" cols="80" onchange="enc_output.value=encodeURIComponent(this.value);" id="enc_input" placeholder="Type here to encode"></textarea>
<textarea rows="10" cols="80" onchange="enc_input.value=decodeURIComponent(this.value);"  id="enc_output"></textarea>
</p>



<p>Base64 encode</p>

<p>
<textarea rows="10" cols="80" onchange="base_output.value=btoa(this.value);" id="base_input" placeholder="Type here to encode"></textarea>
<textarea rows="10" cols="80" onchange="base_input.value=atob(this.value);"  id="base_output"></textarea>
</p>