Example 1: how to reset input field in javascript
document.querySelector('#counter').value = '';
Example 2: html reset code
html, body, div, span, object, iframe,h1, h2, h3, h4, h5, h6, p, blockquote, pre,abbr, address, cite, code,del, dfn, em, img, ins, kbd, q, samp,small, strong, sub, sup, var,b, i,dl, dt, dd, ol, ul, li,fieldset, form, label, legend,table, caption, tbody, tfoot, thead, tr, th, td,article, aside, canvas, details, figcaption, figure, footer, header, hgroup, menu, nav, section, summary,time, mark, audio, video { margin:0; padding:0; border:0; outline:0; font-size:100%; vertical-align:baseline; background:transparent;}body { line-height:1;}article,aside,details,figcaption,figure,footer,header,hgroup,menu,nav,section { display:block;}nav ul { list-style:none;}blockquote, q { quotes:none;}blockquote:before, blockquote:after,q:before, q:after { content:''; content:none;}a { margin:0; padding:0; font-size:100%; vertical-align:baseline; background:transparent;}ins { background-color:#ff9; color:#000; text-decoration:none;}mark { background-color:#ff9; color:#000; font-style:italic; font-weight:bold;}del { text-decoration: line-through;}abbr[title], dfn[title] { border-bottom:1px dotted; cursor:help;}table { border-collapse:collapse; border-spacing:0;}hr { display:block; height:1px; border:0; border-top:1px solid #cccccc; margin:1em 0; padding:0;}input, select { vertical-align:middle;}