( function (win, lib) { var doc = win.document; var docEl = doc.documentElement; var metaEl = doc.querySelector( 'meta[name="viewport"]' ); var flexibleEl = doc.querySelector( 'meta[name="flexible"]' ); var dpr = 0; var scale = 0; var tid; var flexible = lib.flexible || (lib.flexible = {}); if (metaEl) { //console.warn('将根据已有的meta标签来设置缩放比例'); var match = metaEl.getAttribute( 'content' ).match(/initial\-scale=([\d\.]+)/); if (match) { scale = parseFloat(match[1]); dpr = parseInt(1 / scale); } } else if (flexibleEl) { var content = flexibleEl.getAttribute( 'content' ); if (content) { var initialDpr = content.match(/initial\-dpr=([\d\.]+)/); var maximumDpr = content.match(/maximum\-dpr=([\d\.]+)/); if (initialDpr) { dpr = parseFloat(initialDpr[1]); scale = parseFloat((1 / dpr).toFixed(2)); } if (maximumDpr) { dpr = parseFloat(maximumDpr[1]); scale = parseFloat((1 / dpr).toFixed(2)); } } } if (!dpr && !scale) { var isAndroid = win.navigator.appVersion.match(/android/gi); var isIPhone = win.navigator.appVersion.match(/iphone/gi); var devicePixelRatio = win.devicePixelRatio; if (isIPhone) { // iOS下,对于2和3的屏,用2倍的方案,其余的用1倍方案 if (devicePixelRatio >= 3 && (!dpr || dpr >= 3)) { dpr = 3; } else if (devicePixelRatio >= 2 && (!dpr || dpr >= 2)){ dpr = 2; } else { dpr = 1; } } else { // 其他设备下,仍旧使用1倍的方案 dpr = 1; } scale = 1 / dpr; } docEl.setAttribute( 'data-dpr' , dpr); if (!metaEl) { metaEl = doc.createElement( 'meta' ); metaEl.setAttribute( 'name' , 'viewport' ); metaEl.setAttribute( 'content' , 'initial-scale=' + scale + ', maximum-scale=' + scale + ', minimum-scale=' + scale + ', user-scalable=no' ); if (docEl.firstElementChild) { docEl.firstElementChild.appendChild(metaEl); } else { var wrap = doc.createElement( 'div' ); wrap.appendChild(metaEl); doc.write(wrap.innerHTML); } } function refreshRem(){ var width = docEl.getBoundingClientRect().width; if (width / dpr > 540) { width = 540 * dpr; } var rem = width / 10; docEl.style.fontSize = rem + 'px' ; flexible.rem = win.rem = rem; } win.addEventListener( 'resize' , function () { clearTimeout(tid); tid = setTimeout(refreshRem, 300); }, false ); win.addEventListener( 'pageshow' , function (e) { if (e.persisted) { clearTimeout(tid); tid = setTimeout(refreshRem, 300); } }, false ); if (doc.readyState === 'complete' ) { doc.body.style.fontSize = 12 * dpr + 'px' ; } else { doc.addEventListener( 'DOMContentLoaded' , function (e) { doc.body.style.fontSize = 12 * dpr + 'px' ; }, false ); } refreshRem(); flexible.dpr = win.dpr = dpr; flexible.refreshRem = refreshRem; flexible.rem2px = function (d) { var val = parseFloat(d) * this .rem; if ( typeof d === 'string' && d.match(/rem$/)) { val += 'px' ; } return val; } flexible.px2rem = function (d) { var val = parseFloat(d) / this .rem; if ( typeof d === 'string' && d.match(/px$/)) { val += 'rem' ; } return val; } })(window, window[ 'lib' ] || (window[ 'lib' ] = {})); |