WebGL drawBuffer outputs black textures

I am trying to write simple webgl multipass program with the help of drawBuffers. I create 2 drawBuffer textures and assign color to them in fragmentShaderPass1. Texture1 should be green and Texture2 should be brown. Then I pass these textures as a uniform to fragmentShaderPass2 which uses color of the Texture1 to render rectangle. Problem is that rectangle is always black instead of green! What am I doing wrong here?

    // STAGE 1
    let fragmentShaderPass1 = `
        #extension GL_EXT_draw_buffers : require
        precision highp float;
        precision highp int;
        precision highp sampler2D;

        void main( void )
        {
            gl_FragData[0] = vec4(.2, .8, .0, 1);  // green
            gl_FragData[1] = vec4(.6, .5, .4, .3);  // brown
        }
    `;
    let pass1_prog = createProgram(gl, globals.vertexShader, fragmentShaderPass1);

    let firstStageFrameBuffer = gl.createFramebuffer();
    gl.bindFramebuffer(gl.FRAMEBUFFER, firstStageFrameBuffer);

    gl.useProgram(pass1_prog);

    for (let i = 0; i < 2; i++) 
    {
        let tex = gl.createTexture();
        textures.push(tex);

        gl.bindTexture(gl.TEXTURE_2D, tex);

        gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, canvas.width, canvas.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);

        // attach texture to framebuffer
        gl.framebufferTexture2D(gl.FRAMEBUFFER, ext.COLOR_ATTACHMENT0_WEBGL + i, gl.TEXTURE_2D, tex, 0);
    }

    gl.disable(gl.DEPTH_TEST); // framebuffer doesn't even have a depth buffer!
    gl.viewport(0, 0, _this.canvas.width, _this.canvas.height); 

    ext.drawBuffersWEBGL([
        ext.COLOR_ATTACHMENT0_WEBGL,
        ext.COLOR_ATTACHMENT1_WEBGL
    ]);

    gl.drawArrays(gl.POINTS, 0, 1); 



    // STAGE 2
    let fragmentShaderPass2 = `
        precision highp float;
        precision highp int;
        precision highp sampler2D;

        uniform sampler2D inColor0;
        uniform sampler2D inColor1;

        void main( void )
        {
            gl_FragColor = texture2D(inColor0, vec2(0.5));
        }
    `;
    let pass2_prog = createProgram(gl, globals.vertexShader, fragmentShaderPass2);

    gl.bindFramebuffer(gl.FRAMEBUFFER, null);

    gl.useProgram(pass2_prog);
    gl.viewport(0, 0, canvas.width, canvas.height); 
    gl.clearColor(1.0, 1.0, 1.0, 1.0);

    gl.activeTexture(gl.TEXTURE0);
    gl.bindTexture(gl.TEXTURE_2D, textures[0]);
    gl.uniform1i(gl.getUniformLocation(pass2_prog, "inColor0"), 0);

    gl.activeTexture(gl.TEXTURE1);
    gl.bindTexture(gl.TEXTURE_2D, textures[1]); 
    gl.uniform1i(gl.getUniformLocation(pass2_prog, "inColor1"), 1);

    gl.drawArrays(gl.POINTS, 0, 1);