JoeKeikun

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Element

Box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent
• elem.clientLeft, elem.clientTop, elem.clientWidth, elem.clientHeight
• elem.getClientRects(), elem.getBoundingClientRect()

JoeKeikun

var canvasData = context.getImageData(0, 0, canvas.width, canvas.height);
// 转换灰度图
for (var x = 0; x < canvasData.width; x++) {
    for (var y = 0; y < canvasData.height; y++) {

        // Index of the pixel in the array  
        var idx = (x + y * canvasData.width) * 4;
        var r = canvasData.data[idx + 0];
        var g = canvasData.data[idx + 1];
        var b = canvasData.data[idx + 2];

JoeKeikun

/* 
用途：检查输入的Email信箱格式是否正确 
输入：strEmail：字符串 
返回：如果通过验证返回true,否则返回false 
*/
function checkEmail(strEmail) 
{
    //var emailReg = /^[_a-z0-9]+@([_a-z0-9]+\.)+[a-z0-9]{2,3}$/; 
    var emailReg = /^[\w-]+(\.[\w-]+)*@[\w-]+(\.[\w-]+)+$/;
    if ( emailReg.test(strEmail) ) {

JoeKeikun

    $('div').mouseup(function() {
        alert(getSelectedText());
    });

    function getSelectedText() {
        if (window.getSelection) {
            return window.getSelection().toString();
        } else if (document.selection) {
            return document.selection.createRange().text;
        }

JoeKeikun

[HTML]
<div class='box'> 
	<div class='content'>Aspect ratio of 1:1</div> 
</div>



[CSS]
.box{
	position: relative;

JoeKeikun

  var waterdrop = function() {};

  /**
   * 通过入参，计算组成水滴形状的两条贝塞尔曲线控制点.
   *
   * @method getBezierPoints
   *
   * @param  {Number} x 起始点x轴坐标
   * @param  {Number} y 起始点x轴坐标
   * @param  {Number} deltaX 起始点x轴上的间距

JoeKeikun

  var timingfunction = {};

  /**
   * linear 函数
   *
   * @param  {Number} p 正常百分比值
   * @return {Number}  换算后的结果
   */
  timingfunction.linear = function(p) {
    return p;

JoeKeikun

When I developed an app for ios by phonegap, I had a trouble in changing the <input> input cursor color.

but now, there is a solution for it:

---------------
<style>
input {
  color: rgb(60, 0, 248);  /* change [input cursor color] by this*/
  text-shadow: 0px 0px 0px #D60B0B; /* change [input font] by this*/
  -webkit-text-fill-color: transparent;