使用JavaScript创建的SVG路径没有宽度或高度

Question

我正在尝试使用JavaScript和SVG编程创建一个圆角。该角是成功创建的，但是path始终设置为0宽度和0高度。

如果我复制创建的字符串元素并将其粘贴到文件中，那么它可以正常工作，而无需任何问题。

的第二行中所示。

为什么只有在编程中创建的路径没有宽度和高度？我想念什么？

var cornerTopLeft = createCorner("top-left");
applyCornerStyles.call(cornerTopLeft, 0, 0, 10);
var body = document.getElementsByTagName("body")[0];
body.appendChild(cornerTopLeft);
function createCorner(cornerPosition) {
  var corner = document.createElement("svg");
  corner.setAttribute("fill", "red");
  corner.setAttribute("style", "width:10px;height:10px;background-color: red;");
  corner.setAttribute("viewBox", "0 0 100 100");
  corner.setAttribute("xmlns", "http://www.w3.org/2000/svg")
  corner.innerHTML = '<path class="" style="background-color: rgba(0, 0, 0, .5);fill: rgba(0, 0, 0, .5);" d="M100 0 ,Q 0 0 0 100, L0 0, Z"></path>';
  return corner;
}
function applyCornerStyles(top, left, size) {
  this.style.top = top + "px";
  this.style.left = left + "px";
  this.style.width = size + "px";
  this.style.height = size + "px";
  this.style.zIndex = "20002";
  this.style.position = "absolute";
}

<h3>This svg was created using svg string created programatcally.</h3>
<svg fill="none" viewbox="0 0 100 100" xmlns="http://www.w3.org/2000/svg" style="top: 22px; left: 510px; width: 10px; height: 10px; z-index: 20001; position: absolute;">
  <path class="" style="background-color: rgba(0, 0, 0, .5);fill: rgba(0, 0, 0, .5);" d="M100 0 ,Q 0 0 0 100, L0 0, Z"></path>
</svg>

（小提琴）

Answer 1

为了创建一个新的SVG元素，您需要使用document.createElementNS而不是document.createElement。

还需要使用document.createElementNS创建路径。 corner.innerHTML = '<path class=...不会。

const SVG_NS = 'http://www.w3.org/2000/svg';
var cornerTopLeft = createCorner("top-left");
applyCornerStyles.call(cornerTopLeft, 0, 0, 10);
var body = document.getElementsByTagName("body")[0];
body.appendChild(cornerTopLeft);
function createCorner(cornerPosition) {
  var corner = document.createElementNS(SVG_NS, 'svg');
  corner.setAttributeNS(null,"fill", "red");
  corner.setAttribute("class","corner")
  corner.setAttributeNS(null,"viewBox", "0 0 100 100");
  //corner.setAttribute("xmlns", "http://www.w3.org/2000/svg")
  var path = document.createElementNS(SVG_NS, 'path');
  path.setAttributeNS(null,"fill", "rgba(0, 0, 0, .5)");
  path.setAttributeNS(null,"d","M100 0 ,Q 0 0 0 100, L0 0, Z");
  corner.appendChild(path)
  return corner;
}

function applyCornerStyles(top, left, size) {
  this.style.top = top + "px";
  this.style.left = left + "px";
  this.style.width = size + "px";
  this.style.height = size + "px";
  
  this.style.position = "absolute";
}

svg{border:1px solid}
.corner{background-color: red;}

<h3>This svg was created using svg string created programatcally.</h3>
<svg fill="none" viewbox="0 0 100 100" xmlns="http://www.w3.org/2000/svg" style="top: 22px; left: 510px; width: 10px; height: 10px; z-index: 20001; position: absolute;">
  <path class="" style="background-color: rgba(0, 0, 0, .5);fill: rgba(0, 0, 0, .5);" d="M100 0 ,Q 0 0 0 100, L0 0, Z"></path>
</svg>

Answer 2

使用var corner = document.createElementNS("http://www.w3.org/2000/svg", "svg");代替var corner = document.createElement("svg");