Download html page content, One can follow as:
Specify the ref to the element, whose content you want to download as pdf
<div ref="content">
   ....
   ..
</div>
Create a button download like
<button @click="downloadWithCSS">Download PDF</button>
Make sure to add & import jsPDF library into vue-component
import jsPDF from 'jspdf' 
import domtoimage from "dom-to-image";
Specify the method into the VUE component like
methods: {
 downloadWithCSS() {
   /** WITH CSS */
    domtoimage
    .toPng(this.$refs.content)
    .then(function(dataUrl) {
      var img = new Image();
      img.src = dataUrl;
      const doc = new jsPDF({
        orientation: "portrait",
        // unit: "pt",
        format: [900, 1400]
      });
      doc.addImage(img, "JPEG", 20, 20);
      const date = new Date();
      const filename =
        "timechart_" +
        date.getFullYear() +
        ("0" + (date.getMonth() + 1)).slice(-2) +
        ("0" + date.getDate()).slice(-2) +
        ("0" + date.getHours()).slice(-2) +
        ("0" + date.getMinutes()).slice(-2) +
        ("0" + date.getSeconds()).slice(-2) +
        ".pdf";
      doc.save(filename);
    })
    .catch(function(error) {
      console.error("oops, something went wrong!", error);
    });
 },
}