Angular 2 how to execute script tag from innerHTML

Question

I have load the HTML page by http.get() method, and i add content this page to div tag.

getRequestToAssignPage (param: string) : any {

    return this.$http.get(param)
        .map((res: Response) => {

            this.status = res;

            return res.text();
        })
        .toPromise()
        .then(response => {



            let restr: string = response;



            restr = restr.replace(/(<head[^>]*)(?:[^])*?\/head>/ig, '')
                .replace(/(<(\/?)body([^>]*?)>)/g, '')
                .replace(/(<style[^>]*)(?:[^])*?\/style>/g, '')
                .replace(/(<(\/?)html([^>]*?)>)/g, '')
                .replace(/(<app-root[^>]*)(?:[^])*?\/app-root>/ig, '')
                .replace(/(<\?[\s\S]*?\?>)|(<!DOCTYPE\s+\w+\s+\[[\s\S]*?\]>)|(<!\w[\s\S]*?>)/g, '')
                .replace(/(href\s*=\s*(?:"))/ig, 'href="/#')
                .replace(/(href\s*=\s*(?:'))/ig, "href='/#");



            this.response = restr;


        })
        .catch(error => this.status = error );

}

How you do you see, this method, put response in variable, and parse string by regular expressions Ok, and next I add it to div, like this

<div [innerHTML]="response | safe"></div>

Good, my page is display. But, scripts doesn't work. They are exist in the div tag, but doesn't execute.

I had tried do that with eval() but this finished by poorly

let scripts: string[] = restr.match(/\<scr[\s\S]*?ipt>/g);

            this.srcfield.nativeElement.innerHTML = '';

            scripts.forEach((value, index) => {
                eval.call(null, (this.srcfield.nativeElement.innerHTML = value));
            });

SyntaxError: Unexpected token <

Why innerHTML doesn't execute loaded script tags? How i can fix that?

Answer 1

In your template, you can set up something like:

<div #htmlContainer [innerHTML]="trustedHTML"></div>

In the corresponding component, you can load your HTML into your template, build up an array of script tags, and eval each one:

@ViewChild('htmlContainer') container;

ngOnInit() {
  this.http.get('html-file.html').subscribe((res: Response) => {
    this.trustedHTML = this.sanitizer.bypassSecurityTrustHtml(res.text());

    setTimeout(() => { //wait for DOM rendering
      let scripts = this.container.nativeElement.getElementsByTagName('script');
      for (let script of scripts){
        eval(script.text)
      }
    })

  });

I hate that I have to resort to using setTimeout and eval for something so seemingly simple, but it works.

...but not for <script src=".... I ended up importing jQuery and using $(parent).load(url);. If someone has a pure Angular solution, please post it.

Answer 2

Based on the Adam's solution you can implement a custom directive along with the pipe and re-insert scripts into the DOM. This would account for both cases: inline scripts and "src" scripts. Keep in mind that allowing scripts like so is very dangerous.

Pipe:

import { Pipe, PipeTransform } from '@angular/core';
import { DomSanitizer } from '@angular/platform-browser';

@Pipe({ name: 'safeHtml' })
export class SafeHtmlPipe implements PipeTransform {
    constructor(private sanitizer: DomSanitizer) { }

    transform(html) {
        return this.sanitizer.bypassSecurityTrustHtml(html);
    }
}

Directive:

import { Directive, ElementRef, OnInit } from '@angular/core';

@Directive({ selector: '[runScripts]' })
export class RunScriptsDirective implements OnInit {
    constructor(private elementRef: ElementRef) { }
    ngOnInit(): void {
        setTimeout(() => { // wait for DOM rendering
            this.reinsertScripts();
        });
    }
    reinsertScripts(): void {
        const scripts = <HTMLScriptElement[]>this.elementRef.nativeElement.getElementsByTagName('script');
        const scriptsInitialLength = scripts.length;
        for (let i = 0; i < scriptsInitialLength; i++) {
            const script = scripts[i];
            const scriptCopy = <HTMLScriptElement>document.createElement('script');
            scriptCopy.type = script.type ? script.type : 'text/javascript';
            if (script.innerHTML) {
                scriptCopy.innerHTML = script.innerHTML;
            } else if (script.src) {
                scriptCopy.src = script.src;
            }
            scriptCopy.async = false;
            script.parentNode.replaceChild(scriptCopy, script);
        }
    }
}

Usage:

<div [innerHTML]="myDynamicMarkup | safeHtml" runScripts></div>