Adding JS into the html (SyntaxError: Unexpected token ILLEGAL)

Question

I am trying to add a little js code into the html of an external webpage using chrome console. I would use iMacros but it has very limited capabilities for my needs.

This is just an example:

document.getElementById('x').innerHTML = 
"<script type='text/javascript'>
alert(\"yes\");
</script>";

When I run it, it says "SyntaxError: Unexpected token ILLEGAL". Is there any workaround or how can I do what I want to do?

"HTML5 specifies that a <script> tag inserted via innerHTML should not execute." developer.mozilla.org/en-US/docs/Web/API/Element.innerHTML — Felix Kling
– Felix Kling, Commented Feb 1, 2014 at 22:55
Thanks. I solved it with document.getElementsByTagName('html')[0].innerHTML and document.write :) — user1055645
– user1055645, Commented Feb 1, 2014 at 22:59

Dennis · Accepted Answer · 2014-02-01 22:45:11Z

1

You can't include line breaks in a string without escaping. Either put it on one line:

document.getElementById('x').innerHTML = "<script type='text/javascript'>alert(\"yes\");</script>";

or escape with a backslash before the newline

document.getElementById('x').innerHTML = 
"<script type='text/javascript'>\
alert(\"yes\");\
</script>";

answered Feb 1, 2014 at 22:45

Dennis

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2 Comments

user1055645 Over a year ago

Thank you. It doesn't give any error but still it doesn't alert. I mean the JS code doesn't work after I insert it into the HTML. How can I make it work? I tried setInterval.

Felix Kling Over a year ago

@noarm: "HTML5 specifies that a <script> tag inserted via innerHTML should not execute." developer.mozilla.org/en-US/docs/Web/API/Element.innerHTML

Rimpy · Accepted Answer · 2014-02-01 22:45:19Z

1

Write your code in single line

document.getElementById('x').innerHTML = 
"<script type='text/javascript'> alert(\"yes\");</script>";

OR

Use \ to make it multi-line variable

document.getElementById('x').innerHTML = 
"<script type='text/javascript'>\
alert(\"yes\");\
</script>";

OR

Use simple string concatenation

document.getElementById('x').innerHTML = 
    "<script type='text/javascript'>" +
    "alert(\"yes\");" +
    "</script>";

answered Feb 1, 2014 at 22:45

Rimpy

88811 silver badges15 bronze badges

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