noise1 - no matching overloaded function found error message

I am reading the The OpenGL® Shading Language (Language Version: 1.2) http://www.opengl.org/registry/doc/GLSLangSpec.Full.1.20.8.pdf mentions, "8.9 Noise Functions - Noise functions are available to both fragment and vertex shaders. ".

I have the following code snippet on my fragment shader:

			float x = 0.5;
			float noise = noise1(x);

It gives me the following error:

ERROR: 0:26: 'noise1' : no matching overloaded function found 

What did I do wrong?

Thanks in advance for your help.

It seems that WebGL uses GLSL version 1.0

The OpenGL 2.0 GLSL version 1.0 http://www.khronos.org/registry/gles/specs/2.0/GLSL_ES_Specification_1.0.17.pdf does not seem to provide noise1 function.

For a random float can pass a uniform with a random value given by Javascript:
var rand = Math.random () * 100000;

For a random vector can send a uniform sampler2D of a noisy texture