InputField.characterLimit

Description

How many characters the input field is limited to. 0 = infinite.

#pragma strict
// Required when Using UI elements.
public class Example {
    public var mainInputField;
    public var playerName;
    function Start() {
        //Changes the character limit in the main input field.
        mainInputField.characterLimit = playerName.Length;
    }
}

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // Required when Using UI elements.

public class Example : MonoBehaviour
{
    public InputField mainInputField;
    public string playerName;

    void Start()
    {
        //Changes the character limit in the main input field.
        mainInputField.characterLimit = playerName.Length;
    }
}