> For the complete documentation index, see [llms.txt](https://200ok.gitbook.io/200ok-documents/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://200ok.gitbook.io/200ok-documents/user-manual/built-in-functions/logical/isnumber.md).

# isNumber

isNumber() function is the Standard function available in 200OK.

**Description** : The isNumber function checks if a given text value represents a number and returns TRUE if it does, otherwise FALSE.

**Syntax** : fx\_isNumber(Text)

**Example** : fx\_isNumber(two) returns false, while fx\_isNumber(2) returns true.

**Scenario** : In a form validation system, a web developer is implementing client-side validation to ensure that numeric input fields contain valid numbers. They utilize a function to check if the user-provided text is a valid number. If the text is a valid number, the system accepts it; otherwise, it prompts the user to enter a valid numeric value.

**Request Side** : 

<figure><img src="https://lh7-us.googleusercontent.com/lE-bZLDq8nrMClM9IVdCug7LKZ_fyFyQB6Ez_Pvm6voDl93E1HmGzYOeHjPEOXIbcTzgJfGxTwxgms6nLKQANtfJ2wuWVy_LHlNUvLioo4IXKvf7O9v8DPQE2UWNGAo9DS1Jl-n3DYHdKtnK8GEeyKA" alt=""><figcaption></figcaption></figure>

<figure><img src="https://lh7-us.googleusercontent.com/gORHdeZQegAJjpCEFjy0FdiXa328u9_ZSCy2yB6VnjtdCEW6q4l-TxUzUaosc_ObUCpcgfD9Ql7lluPtC8qNOHzcQRVmzWHsDzNMxjfndszyZ6H24ACoyloJYdiH3q7YqROYybyaLmueAW5pf8bXU5s" alt=""><figcaption></figcaption></figure>

<figure><img src="https://lh7-us.googleusercontent.com/_-JQROEqFvAGiarIRgwKa6Zsd8YCL5Lodp2Aw9ksCEqGKMPri01SToEe2ki7dJRyBx5GDdK8_VFg-cT-O4MZXC47CeXfpxGSZoc90W8HLBmxatJjPp2WeN4_qnvFmxlfhNyGqX7HUuHzMFw1pay6Axs" alt=""><figcaption></figcaption></figure>

<figure><img src="https://lh7-us.googleusercontent.com/N5TJNJvushWC-9lS7pX_Anq5sFVirY6YRIxcywFng2WAlbgeNDiX_oSG_TC0IVr3U2Z0ogjkklAST9K87DpQLNL4t58dQIxMEuvBGb5NWeQgAOxARiTvcoKiPXUs9-zLmg5OvnUszjcs3zxzL7VUDIc" alt=""><figcaption></figcaption></figure>

**Response Side** :&#x20;

<figure><img src="https://lh7-us.googleusercontent.com/BHO60zUsBLc-jtikwmEQGrsepqrx-u3FS87MK55-RYvgW2YDD2tZIKwyDIxrwJ7fqxnb22z1v-1YcQz-qHY3-fP8GkBuIS7--2NcpxAUQN_IudpJP7JRyKACmMZ9DluBd4Yn8envVBGeI8kjM6o0Kos" alt=""><figcaption></figcaption></figure>

<figure><img src="https://lh7-us.googleusercontent.com/fhxA-GXs7tf9Dx_RjuHxfjJUT3FUAftEB-akeENc6bf_iibgFbVZr3DSoZGoK0uIfnY7cBF16DcR418w3D3A2k98d8EgpvPIITPPkiSD_N3ktqM5-ksgqMJ5np4rTH0QhYJlwtNU6CqLG5QCli5GG3g" alt=""><figcaption></figcaption></figure>