Scripting
One can override default browser behaviors with the evt.preventDefault() method, add event listeners to objects with the syntax element.addEventListener(event, function, useCapture), and set element properties with syntax like svgElement.style.setProperty("fill-opacity", "0.0", ""). Note the existence of all three arguments setting properties.
Preventing default behavior in event code
When writing drag and drop code, sometimes you'll find that text on the page gets accidentally selected while dragging. Or if you want to use the backspace key in your code, you want to override the browser's default behavior when the backspace key is pressed, which is to go back to the previous page. The evt.preventDefault() method lets you do this.
Using eventListeners with objects
The methods addEventListener() and removeEventListener() are very useful when writing interactive SVG. You can pass an object that implements the handleEvent interface as the second parameter to these methods.
function myRect(x, y, w, h, message) {
this.message = message;
this.rect = document.createElementNS("http://www.w3.org/2000/svg", "rect");
this.rect.setAttributeNS(null, "x", x);
this.rect.setAttributeNS(null, "y", y);
this.rect.setAttributeNS(null, "width", w);
this.rect.setAttributeNS(null, "height", h);
document.documentElement.appendChild(this.rect);
this.rect.addEventListener("click", this, false);
this.handleEvent = (evt) => {
switch (evt.type) {
case "click":
alert(this.message);
break;
}
};
}
Inter-document scripting: referencing embedded SVG
When using SVG within HTML, Adobe's SVG Viewer 3.0 automatically includes a window property called svgDocument that points to the SVG document. This is not the case for Mozilla's native SVG implementation; therefore, using window.svgDocument does not work in Mozilla. Instead, you can use
const svgDoc = document.embeds["name_of_svg"].getSVGDocument();
to get a reference to an embedded SVG document instead.
The best way to get access to the Document representing an SVG document is to look at HTMLIFrameElement.contentDocument (if the document is presented in an <iframe>) or HTMLObjectElement.contentDocument (if the document is presented in an <object> element), like this:
const svgDoc = document.getElementById("iframe_element").contentDocument;
In addition, the <iframe>, <embed>, and <object> elements offer a method, getSVGDocument(), which returns the XMLDocument representing the element's embedded SVG or null if the element doesn't represent an SVG document.
You can also use document.getElementById("svg_elem_name").getSVGDocument(), which gives the same result.
Note:
You may find documentation referring to an SVGDocument interface. Prior to SVG 2, SVG documents were represented using that interface. However, SVG documents are now represented using the XMLDocument interface instead.
Inter-document scripting: calling JavaScript functions
When calling a JavaScript function that resides in the HTML file from an SVG file that is embedded in an HTML document, you should use parent.functionName() to reference the function. Although the Adobe SVG viewer plugin allows the use of functionName(), it's not the preferred way to do things.
Note:
According to the SVG wiki the "parent" JS variable is broken in Adobe's SVG version 6 preview plugin. The suggested workaround is to use "top" instead of "parent". Since it is a beta version of their plugin, we can probably safely ignore this.
More information and some examples can be found on the SVG wiki inter-document scripting page.
setProperty has three parameters
The function svgElement.style.setProperty("fill-opacity", "0.0") throws a DOMException - SYNTAX ERR in Mozilla. This behavior is specified by the W3C in the DOM Level 2 Style Specification. The function setProperty is defined as a function with three parameters. The above can be replaced with 'svgElement.style.setProperty("fill-opacity", "0.0", "")', which is standards compliant.