Question

1. (02.04 mc) which javascript code segment displays notebook after it is executed? (2 points) console.log(\keynote\.substr(3, 4) + \textbook\.substr(4, 4)); console.log(\keynote\.substr(2, 4) + \textbook\.substr(4, 4)); console.log(\keynote\.substr(4, 4) + \textbook\.substr(4, 4)); console.log(\keynote\.substr(3, 4) + \textbook\.substr(5, 4));

Explanation:

Step1: Recall substr function

The substr function in JavaScript takes two arguments: the starting index and the number of characters to extract.

Step2: Analyze first option

For console.log("keynote".substr(3, 4) + "textbook".substr(4, 4)):

• "keynote".substr(3, 4) extracts "note" (starting at index 3, 4 characters).
• "textbook".substr(4, 4) extracts "book". The result is "notebook".

Step3: Analyze second option

For console.log("keynote".substr(2, 4) + "textbook".substr(4, 4)):

• "keynote".substr(2, 4) extracts "ynot", result is "ynotbook".

Step4: Analyze third option

For console.log("keynote".substr(4, 4) + "textbook".substr(4, 4)):

• "keynote".substr(4, 4) extracts "note" but starting at a different index than needed for "note" to combine right, result is not "notebook".

Step5: Analyze fourth option

For console.log("keynote".substr(3, 4) + "textbook".substr(5, 4)):

• "textbook".substr(5, 4) extracts "tboo", result is "notetboo".

Answer:

console.log("keynote".substr(3, 4) + "textbook".substr(4, 4));