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November 28, 2019 16:13
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počítání znaků ve stylu Twitteru
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title>počítačka znaků</title> | |
| <style> | |
| output.count-chars { | |
| display: inline-block; | |
| position: relative; | |
| min-width: 30px; | |
| min-height: 30px; | |
| padding-top: 0; | |
| border-radius: 50%; | |
| margin: 0.5em 0 1em 0; | |
| float: right; | |
| } | |
| output.count-chars::before { | |
| content: ''; | |
| position: absolute; | |
| width: calc(100% - (2 * 3px)); | |
| height: calc(100% - (2 * 3px)); | |
| margin: 3px; | |
| background: #d6dbe0; | |
| border-radius: 50%; | |
| } | |
| output.count-chars span { | |
| position: relative; | |
| display: inline-block; | |
| z-index: 1; | |
| text-align: center; | |
| width: 100%; | |
| margin-top: 5px; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <textarea class="max-length-counter-js 160">náhodný příklad</textarea> | |
| <script> | |
| ( () => | |
| { | |
| 'use strict'; | |
| const OUTPUT_NODE_NAME = 'OUTPUT'; | |
| const OUTPUT_CLASS_NAME = 'count-chars'; | |
| const HIDE_RESULT_MORE_THAN = 99; // in chars | |
| const GOOD_COLOR_MORE_THAN = 50; // in chars | |
| const COLORS_MATRIX = { | |
| 'thermometerBackground': '#ccc', | |
| 'normal': 'orange', | |
| 'good': 'green', | |
| 'bad': 'red', | |
| }; | |
| const createResultElementAfter = ( /** @type {HTMLInputElement | HTMLTextAreaElement} */ inputElement ) => | |
| { | |
| const countElement = document.createElement( OUTPUT_NODE_NAME ); | |
| countElement.className = OUTPUT_CLASS_NAME; | |
| const span = document.createElement( 'span' ); | |
| countElement.appendChild( span ); | |
| inputElement.parentNode.insertBefore( countElement, inputElement.nextSibling ); | |
| return countElement; | |
| }; | |
| const drawVisualLengthInfoIn = ( /** @type {HTMLOutputElement} */ resultElement, /** @type {Number} */ textLength, /** @type {Number} */ maxChars ) => | |
| { | |
| const PERCENT_100 = 100; | |
| const remainingChars = maxChars - textLength; | |
| if ( remainingChars <= HIDE_RESULT_MORE_THAN ) { | |
| resultElement.lastElementChild.textContent = remainingChars; | |
| } else { | |
| resultElement.lastElementChild.textContent = ''; | |
| } | |
| let percent = PERCENT_100 - ( ( PERCENT_100 / maxChars ) * remainingChars ); | |
| let color = COLORS_MATRIX.normal; | |
| if ( percent > PERCENT_100 ) { | |
| color = COLORS_MATRIX.bad; | |
| percent = percent - PERCENT_100; | |
| } else if ( textLength >= GOOD_COLOR_MORE_THAN ) { | |
| color = COLORS_MATRIX.good; | |
| } | |
| resultElement.style.backgroundImage = 'linear-gradient(' + color + ' ' + percent + '%, ' + COLORS_MATRIX.thermometerBackground + ' 0)'; // polyfill for FF | |
| resultElement.style.backgroundImage = 'conic-gradient(' + color + ' ' + percent + '%, ' + COLORS_MATRIX.thermometerBackground + ' 0)'; | |
| resultElement.setAttribute( 'aria-valuenow', String( textLength ) ); | |
| resultElement.setAttribute( 'aria-valuemax', String( maxChars ) ); | |
| resultElement.setAttribute( 'aria-valuemin', '0' ); | |
| resultElement.title = String( textLength ) + ' / ' + String( maxChars ) + ' (' + String( percent ) + '%)'; | |
| return true; | |
| }; | |
| const recountChars = ( /** @type {HTMLInputElement | HTMLTextAreaElement} */ inputElement, /** @type {Number} */ maxChars ) => | |
| { | |
| /** @type {HTMLOutputElement} */ | |
| const nes = inputElement.nextElementSibling; | |
| /** @type {HTMLOutputElement} */ | |
| let resultElement; | |
| if ( nes | |
| && nes.nodeType === Node.ELEMENT_NODE | |
| && nes.nodeName === OUTPUT_NODE_NAME | |
| && nes.classList.contains( OUTPUT_CLASS_NAME ) | |
| ) { | |
| resultElement = nes; | |
| } else { | |
| resultElement = createResultElementAfter( inputElement ); | |
| } | |
| return drawVisualLengthInfoIn( resultElement, inputElement.value.length, maxChars ); | |
| }; | |
| HTMLTextAreaElement.prototype.recountChars = function ( /** @type {Number} */ maxChars ) | |
| { | |
| return recountChars( this, maxChars ); | |
| }; | |
| //HTMLInputElement.prototype.recountChars = function ( … // possible but don't need now | |
| window.addEventListener( 'load', () => | |
| { | |
| Array.prototype.slice.call( document.getElementsByClassName( 'max-length-counter-js' ) ).forEach( ( /** @type {HTMLElement} */ element ) => | |
| { | |
| element.classList.forEach( ( /** @type {String} */ singleClass ) => | |
| { | |
| const maxChars = Number( singleClass ); | |
| if ( maxChars ) { | |
| element.addEventListener( 'change', ( /** @type {Event} */ event ) => | |
| { | |
| const eventTarget = event.target; | |
| eventTarget.recountChars( maxChars ); | |
| }, false ); | |
| element.addEventListener( 'keydown', ( /** @type {Event} */ event ) => | |
| { | |
| const eventTarget = event.target; | |
| eventTarget.recountChars( maxChars ); | |
| }, false ); | |
| element.addEventListener( 'keyup', ( /** @type {Event} */ event ) => | |
| { | |
| const eventTarget = event.target; | |
| eventTarget.recountChars( maxChars ); | |
| }, false ); | |
| element.recountChars( maxChars ); | |
| return true; | |
| } | |
| return false; | |
| } ); | |
| } ); | |
| }, false ); | |
| } )(); | |
| </script> | |
| </body> | |
| </html> |
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