The correct answer is that `hideField` is not a valid method, and the developer should use `setDisplay` or `setVisible` instead. This error occurs because the GlideForm (g_form) API in ServiceNow does not include a `hideField` method; calling an undefined method on the g_form object throws a JavaScript error. To control field visibility in client scripts, `setDisplay('field_name', false)` hides the field while keeping its label, whereas `setVisible('field_name', false)` hides both the field and its label. On the ServiceNow Certified Application Developer (CAD) exam, this question tests your knowledge of the correct g_form API methods for UI manipulation, often appearing as a common trap where candidates assume a generic `hideField` exists. A reliable memory tip is to remember that ServiceNow uses explicit "set" methods: you always "set" a property like display or visibility, never "hide" directly.
SNOW-CAD User Interface Development Practice Question
This SNOW-CAD practice question tests your understanding of user interface development. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
function onChange(control, oldValue, newValue, isLoading, isTemplate) {\n if (isLoading) return;\n if (newValue == '1') {\n g_form.hideField('field2');\n }\n}
Refer to the exhibit. A developer wrote this client script to hide a field when another field changes to '1'. However, the script throws a JavaScript error. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
hideField is not a valid method; the correct method is setDisplay or setVisible.
Option A is correct because `hideField` is not a valid client-side method in ServiceNow. The correct methods to control field visibility in client scripts are `setDisplay` (to show/hide a field) or `setVisible` (to show/hide a field and its label). Using an undefined method like `hideField` will throw a JavaScript error because the GlideForm (g_form) API does not include it.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
hideField is not a valid method; the correct method is setDisplay or setVisible.
Why this is correct
Correct: g_form.setDisplay('field2', false) or g_form.setVisible('field2', false) should be used.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
hideField is a server-side method and cannot be used in client scripts.
Why it's wrong here
Wrong: hideField is not even a server-side method; it's not part of the API.
✗
The developer should use showFieldMsg to hide the field.
Why it's wrong here
Wrong: showFieldMsg displays a message, it does not hide fields.
✗
The function signature is incorrect for an onChange client script.
Why it's wrong here
Wrong: The signature is correct: function onChange(control, oldValue, newValue, isLoading, isTemplate).
Common exam traps
Common exam trap: answer the scenario, not the keyword
ServiceNow often tests the distinction between valid and invalid g_form methods, and the trap here is that candidates may assume `hideField` is a real method because it sounds intuitive, without knowing the exact API names like `setDisplay` or `setVisible`.
Trap categories for this question
Command / output trap
Wrong: showFieldMsg displays a message, it does not hide fields.
Detailed technical explanation
How to think about this question
In ServiceNow client scripts, the `g_form` object provides methods like `setDisplay(fieldName, false)` to hide a field and `setDisplay(fieldName, true)` to show it. The `setVisible` method works similarly but also hides the field label. These methods manipulate the DOM directly by setting the `display` CSS property to 'none' or removing it. A common real-world scenario is hiding a 'Reason' field unless a 'Status' field is set to 'Rejected', where using `g_form.setDisplay('reason', false)` is the correct approach.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
User Interface Development — This question tests User Interface Development — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: hideField is not a valid method; the correct method is setDisplay or setVisible. — Option A is correct because `hideField` is not a valid client-side method in ServiceNow. The correct methods to control field visibility in client scripts are `setDisplay` (to show/hide a field) or `setVisible` (to show/hide a field and its label). Using an undefined method like `hideField` will throw a JavaScript error because the GlideForm (g_form) API does not include it.
What should I do if I get this SNOW-CAD question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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